diff --git a/src/Bridges/DatabaseDI/DatabaseExtension.php b/src/Bridges/DatabaseDI/DatabaseExtension.php
index bd4f06430..692252066 100644
--- a/src/Bridges/DatabaseDI/DatabaseExtension.php
+++ b/src/Bridges/DatabaseDI/DatabaseExtension.php
@@ -33,7 +33,7 @@ class DatabaseExtension extends Nette\DI\CompilerExtension
 	private $debugMode;
 
 
-	public function __construct($debugMode = FALSE)
+	public function __construct(bool $debugMode = FALSE)
 	{
 		$this->debugMode = $debugMode;
 	}
diff --git a/src/Bridges/DatabaseTracy/ConnectionPanel.php b/src/Bridges/DatabaseTracy/ConnectionPanel.php
index 63048a21e..0c470d473 100644
--- a/src/Bridges/DatabaseTracy/ConnectionPanel.php
+++ b/src/Bridges/DatabaseTracy/ConnectionPanel.php
@@ -99,7 +99,7 @@ public static function renderException($e)
 	}
 
 
-	public function getTab()
+	public function getTab(): string
 	{
 		$name = $this->name;
 		$count = $this->count;
@@ -110,11 +110,11 @@ public function getTab()
 	}
 
 
-	public function getPanel()
+	public function getPanel(): ?string
 	{
 		$this->disabled = TRUE;
 		if (!$this->count) {
-			return;
+			return NULL;
 		}
 
 		$name = $this->name;
diff --git a/src/Database/Connection.php b/src/Database/Connection.php
index 148678639..4dc927114 100644
--- a/src/Database/Connection.php
+++ b/src/Database/Connection.php
@@ -118,9 +118,8 @@ public function getSupplementalDriver()
 
 	/**
 	 * @param  string  sequence object
-	 * @return string
 	 */
-	public function getInsertId($name = NULL)
+	public function getInsertId(string $name = NULL): string
 	{
 		try {
 			$res = $this->getPdo()->lastInsertId($name);
@@ -134,9 +133,8 @@ public function getInsertId($name = NULL)
 	/**
 	 * @param  string  string to be quoted
 	 * @param  int     data type hint
-	 * @return string
 	 */
-	public function quote($string, $type = PDO::PARAM_STR)
+	public function quote(string $string, int $type = PDO::PARAM_STR): string
 	{
 		try {
 			return $this->getPdo()->quote($string, $type);
@@ -169,10 +167,8 @@ public function rollBack()
 
 	/**
 	 * Generates and executes SQL query.
-	 * @param  string
-	 * @return ResultSet
 	 */
-	public function query($sql, ...$params)
+	public function query(string $sql, ...$params): ResultSet
 	{
 		[$sql, $params] = $this->preprocess($sql, ...$params);
 		try {
@@ -186,11 +182,7 @@ public function query($sql, ...$params)
 	}
 
 
-	/**
-	 * @param  string
-	 * @return ResultSet
-	 */
-	public function queryArgs($sql, array $params)
+	public function queryArgs(string $sql, array $params): ResultSet
 	{
 		return $this->query($sql, ...$params);
 	}
@@ -213,10 +205,8 @@ public function preprocess($sql, ...$params)
 
 	/**
 	 * Shortcut for query()->fetch()
-	 * @param  string
-	 * @return Row|NULL
 	 */
-	public function fetch($sql, ...$params)
+	public function fetch(string $sql, ...$params): ?Row
 	{
 		return $this->query($sql, ...$params)->fetch();
 	}
@@ -224,10 +214,9 @@ public function fetch($sql, ...$params)
 
 	/**
 	 * Shortcut for query()->fetchField()
-	 * @param  string
 	 * @return mixed
 	 */
-	public function fetchField($sql, ...$params)
+	public function fetchField(string $sql, ...$params)
 	{
 		return $this->query($sql, ...$params)->fetchField();
 	}
@@ -235,10 +224,8 @@ public function fetchField($sql, ...$params)
 
 	/**
 	 * Shortcut for query()->fetchPairs()
-	 * @param  string
-	 * @return array
 	 */
-	public function fetchPairs($sql, ...$params)
+	public function fetchPairs(string $sql, ...$params): array
 	{
 		return $this->query($sql, ...$params)->fetchPairs();
 	}
@@ -246,19 +233,14 @@ public function fetchPairs($sql, ...$params)
 
 	/**
 	 * Shortcut for query()->fetchAll()
-	 * @param  string
-	 * @return array
 	 */
-	public function fetchAll($sql, ...$params)
+	public function fetchAll(string $sql, ...$params): array
 	{
 		return $this->query($sql, ...$params)->fetchAll();
 	}
 
 
-	/**
-	 * @return SqlLiteral
-	 */
-	public static function literal($value, ...$params)
+	public static function literal($value, ...$params): SqlLiteral
 	{
 		return new SqlLiteral($value, $params);
 	}
diff --git a/src/Database/Context.php b/src/Database/Context.php
index 76c4ccee9..03b07fbcc 100644
--- a/src/Database/Context.php
+++ b/src/Database/Context.php
@@ -65,9 +65,8 @@ public function rollBack()
 
 	/**
 	 * @param  string  sequence object
-	 * @return string
 	 */
-	public function getInsertId($name = NULL)
+	public function getInsertId(string $name = NULL): string
 	{
 		return $this->connection->getInsertId($name);
 	}
@@ -75,30 +74,20 @@ public function getInsertId($name = NULL)
 
 	/**
 	 * Generates and executes SQL query.
-	 * @param  string
-	 * @return ResultSet
 	 */
-	public function query($sql, ...$params)
+	public function query(string $sql, ...$params): ResultSet
 	{
 		return $this->connection->query($sql, ...$params);
 	}
 
 
-	/**
-	 * @param  string
-	 * @return ResultSet
-	 */
-	public function queryArgs($sql, array $params)
+	public function queryArgs(string $sql, array $params): ResultSet
 	{
 		return $this->connection->query($sql, ...$params);
 	}
 
 
-	/**
-	 * @param  string
-	 * @return Table\Selection
-	 */
-	public function table($table)
+	public function table(string $table): Table\Selection
 	{
 		return new Table\Selection($this, $this->conventions, $table, $this->cacheStorage);
 	}
@@ -130,10 +119,8 @@ public function getConventions()
 
 	/**
 	 * Shortcut for query()->fetch()
-	 * @param  string
-	 * @return Row|NULL
 	 */
-	public function fetch($sql, ...$params)
+	public function fetch(string $sql, ...$params): ?Row
 	{
 		return $this->connection->query($sql, ...$params)->fetch();
 	}
@@ -141,10 +128,9 @@ public function fetch($sql, ...$params)
 
 	/**
 	 * Shortcut for query()->fetchField()
-	 * @param  string
 	 * @return mixed
 	 */
-	public function fetchField($sql, ...$params)
+	public function fetchField(string $sql, ...$params)
 	{
 		return $this->connection->query($sql, ...$params)->fetchField();
 	}
@@ -152,10 +138,8 @@ public function fetchField($sql, ...$params)
 
 	/**
 	 * Shortcut for query()->fetchPairs()
-	 * @param  string
-	 * @return array
 	 */
-	public function fetchPairs($sql, ...$params)
+	public function fetchPairs(string $sql, ...$params): array
 	{
 		return $this->connection->query($sql, ...$params)->fetchPairs();
 	}
@@ -163,19 +147,14 @@ public function fetchPairs($sql, ...$params)
 
 	/**
 	 * Shortcut for query()->fetchAll()
-	 * @param  string
-	 * @return array
 	 */
-	public function fetchAll($sql, ...$params)
+	public function fetchAll(string $sql, ...$params): array
 	{
 		return $this->connection->query($sql, ...$params)->fetchAll();
 	}
 
 
-	/**
-	 * @return SqlLiteral
-	 */
-	public static function literal($value, ...$params)
+	public static function literal($value, ...$params): SqlLiteral
 	{
 		return new SqlLiteral($value, $params);
 	}
diff --git a/src/Database/Conventions/DiscoveredConventions.php b/src/Database/Conventions/DiscoveredConventions.php
index b2910c0b4..d091051f0 100644
--- a/src/Database/Conventions/DiscoveredConventions.php
+++ b/src/Database/Conventions/DiscoveredConventions.php
@@ -28,13 +28,13 @@ public function __construct(IStructure $structure)
 	}
 
 
-	public function getPrimary($table)
+	public function getPrimary(string $table)
 	{
 		return $this->structure->getPrimaryKey($table);
 	}
 
 
-	public function getHasManyReference($nsTable, $key)
+	public function getHasManyReference(string $nsTable, string $key): ?array
 	{
 		$candidates = $columnCandidates = [];
 		$targets = $this->structure->getHasManyReference($nsTable);
@@ -83,7 +83,7 @@ public function getHasManyReference($nsTable, $key)
 	}
 
 
-	public function getBelongsToReference($table, $key)
+	public function getBelongsToReference(string $table, string $key): ?array
 	{
 		$tableColumns = $this->structure->getBelongsToReference($table);
 
diff --git a/src/Database/Conventions/StaticConventions.php b/src/Database/Conventions/StaticConventions.php
index de430bc8e..1a188ae8a 100644
--- a/src/Database/Conventions/StaticConventions.php
+++ b/src/Database/Conventions/StaticConventions.php
@@ -36,7 +36,7 @@ class StaticConventions implements IConventions
 	 * @param  string %1$s stands for key used after ->, %2$s for table name
 	 * @param  string %1$s stands for key used after ->, %2$s for table name
 	 */
-	public function __construct($primary = 'id', $foreign = '%s_id', $table = '%s')
+	public function __construct(string $primary = 'id', string $foreign = '%s_id', string $table = '%s')
 	{
 		$this->primary = $primary;
 		$this->foreign = $foreign;
@@ -44,13 +44,13 @@ public function __construct($primary = 'id', $foreign = '%s_id', $table = '%s')
 	}
 
 
-	public function getPrimary($table)
+	public function getPrimary(string $table)
 	{
 		return sprintf($this->primary, $this->getColumnFromTable($table));
 	}
 
 
-	public function getHasManyReference($table, $key)
+	public function getHasManyReference(string $table, string $key): ?array
 	{
 		$table = $this->getColumnFromTable($table);
 		return [
@@ -60,7 +60,7 @@ public function getHasManyReference($table, $key)
 	}
 
 
-	public function getBelongsToReference($table, $key)
+	public function getBelongsToReference(string $table, string $key): ?array
 	{
 		$table = $this->getColumnFromTable($table);
 		return [
@@ -70,7 +70,7 @@ public function getBelongsToReference($table, $key)
 	}
 
 
-	protected function getColumnFromTable($name)
+	protected function getColumnFromTable(string $name)
 	{
 		if ($this->table !== '%s' && preg_match('(^' . str_replace('%s', '(.*)', preg_quote($this->table)) . '\z)', $name, $match)) {
 			return $match[1];
diff --git a/src/Database/DriverException.php b/src/Database/DriverException.php
index aa2df1920..0f42f8596 100644
--- a/src/Database/DriverException.php
+++ b/src/Database/DriverException.php
@@ -49,7 +49,7 @@ public function getDriverCode()
 	/**
 	 * @return string|NULL  SQLSTATE error code
 	 */
-	public function getSqlState()
+	public function getSqlState(): ?string
 	{
 		return $this->errorInfo[0] ?? NULL;
 	}
@@ -58,7 +58,7 @@ public function getSqlState()
 	/**
 	 * @return string|NULL  SQL command
 	 */
-	public function getQueryString()
+	public function getQueryString(): ?string
 	{
 		return $this->queryString;
 	}
diff --git a/src/Database/Drivers/MsSqlDriver.php b/src/Database/Drivers/MsSqlDriver.php
index 3a917c287..a30a92f4c 100644
--- a/src/Database/Drivers/MsSqlDriver.php
+++ b/src/Database/Drivers/MsSqlDriver.php
@@ -24,7 +24,7 @@ public function initialize(Nette\Database\Connection $connection, array $options
 	}
 
 
-	public function convertException(\PDOException $e)
+	public function convertException(\PDOException $e): Nette\Database\DriverException
 	{
 		return Nette\Database\DriverException::from($e);
 	}
@@ -36,7 +36,7 @@ public function convertException(\PDOException $e)
 	/**
 	 * Delimites identifier for use in a SQL statement.
 	 */
-	public function delimite($name)
+	public function delimite(string $name): string
 	{
 		// @see https://msdn.microsoft.com/en-us/library/ms176027.aspx
 		return '[' . str_replace(['[', ']'], ['[[', ']]'], $name) . ']';
@@ -46,7 +46,7 @@ public function delimite($name)
 	/**
 	 * Formats boolean for use in a SQL statement.
 	 */
-	public function formatBool($value)
+	public function formatBool(bool $value): string
 	{
 		return $value ? '1' : '0';
 	}
@@ -55,7 +55,7 @@ public function formatBool($value)
 	/**
 	 * Formats date-time for use in a SQL statement.
 	 */
-	public function formatDateTime(/*\DateTimeInterface*/ $value)
+	public function formatDateTime(\DateTimeInterface $value): string
 	{
 		return $value->format("'Y-m-d H:i:s'");
 	}
@@ -64,7 +64,7 @@ public function formatDateTime(/*\DateTimeInterface*/ $value)
 	/**
 	 * Formats date-time interval for use in a SQL statement.
 	 */
-	public function formatDateInterval(\DateInterval $value)
+	public function formatDateInterval(\DateInterval $value): string
 	{
 		throw new Nette\NotSupportedException;
 	}
@@ -73,7 +73,7 @@ public function formatDateInterval(\DateInterval $value)
 	/**
 	 * Encodes string for use in a LIKE statement.
 	 */
-	public function formatLike($value, $pos)
+	public function formatLike(string $value, int $pos): string
 	{
 		$value = strtr($value, ["'" => "''", '%' => '[%]', '_' => '[_]', '[' => '[[]']);
 		return ($pos <= 0 ? "'%" : "'") . $value . ($pos >= 0 ? "%'" : "'");
@@ -83,7 +83,7 @@ public function formatLike($value, $pos)
 	/**
 	 * Injects LIMIT/OFFSET to the SQL query.
 	 */
-	public function applyLimit(&$sql, $limit, $offset)
+	public function applyLimit(string &$sql, ?int $limit, ?int $offset)
 	{
 		if ($offset) {
 			throw new Nette\NotSupportedException('Offset is not supported by this database.');
@@ -103,7 +103,7 @@ public function applyLimit(&$sql, $limit, $offset)
 	/**
 	 * Normalizes result row.
 	 */
-	public function normalizeRow($row)
+	public function normalizeRow(array $row): array
 	{
 		return $row;
 	}
@@ -115,7 +115,7 @@ public function normalizeRow($row)
 	/**
 	 * Returns list of tables.
 	 */
-	public function getTables()
+	public function getTables(): array
 	{
 		throw new Nette\NotImplementedException;
 	}
@@ -124,7 +124,7 @@ public function getTables()
 	/**
 	 * Returns metadata for all columns in a table.
 	 */
-	public function getColumns($table)
+	public function getColumns(string $table): array
 	{
 		throw new Nette\NotImplementedException;
 	}
@@ -133,7 +133,7 @@ public function getColumns($table)
 	/**
 	 * Returns metadata for all indexes in a table.
 	 */
-	public function getIndexes($table)
+	public function getIndexes(string $table): array
 	{
 		throw new Nette\NotImplementedException;
 	}
@@ -142,7 +142,7 @@ public function getIndexes($table)
 	/**
 	 * Returns metadata for all foreign keys in a table.
 	 */
-	public function getForeignKeys($table)
+	public function getForeignKeys(string $table): array
 	{
 		throw new Nette\NotImplementedException;
 	}
@@ -151,17 +151,13 @@ public function getForeignKeys($table)
 	/**
 	 * Returns associative array of detected types (IReflection::FIELD_*) in result set.
 	 */
-	public function getColumnTypes(\PDOStatement $statement)
+	public function getColumnTypes(\PDOStatement $statement): array
 	{
 		return Nette\Database\Helpers::detectTypes($statement);
 	}
 
 
-	/**
-	 * @param  string
-	 * @return bool
-	 */
-	public function isSupported($item)
+	public function isSupported(string $item): bool
 	{
 		return $item === self::SUPPORT_SUBSELECT;
 	}
diff --git a/src/Database/Drivers/MySqlDriver.php b/src/Database/Drivers/MySqlDriver.php
index 174ccc019..7a5da2a98 100644
--- a/src/Database/Drivers/MySqlDriver.php
+++ b/src/Database/Drivers/MySqlDriver.php
@@ -46,10 +46,7 @@ public function initialize(Nette\Database\Connection $connection, array $options
 	}
 
 
-	/**
-	 * @return Nette\Database\DriverException
-	 */
-	public function convertException(\PDOException $e)
+	public function convertException(\PDOException $e): Nette\Database\DriverException
 	{
 		$code = $e->errorInfo[1] ?? NULL;
 		if (in_array($code, [1216, 1217, 1451, 1452, 1701], TRUE)) {
@@ -76,7 +73,7 @@ public function convertException(\PDOException $e)
 	/**
 	 * Delimites identifier for use in a SQL statement.
 	 */
-	public function delimite($name)
+	public function delimite(string $name): string
 	{
 		// @see http://dev.mysql.com/doc/refman/5.0/en/identifiers.html
 		return '`' . str_replace('`', '``', $name) . '`';
@@ -86,7 +83,7 @@ public function delimite($name)
 	/**
 	 * Formats boolean for use in a SQL statement.
 	 */
-	public function formatBool($value)
+	public function formatBool(bool $value): string
 	{
 		return $value ? '1' : '0';
 	}
@@ -95,7 +92,7 @@ public function formatBool($value)
 	/**
 	 * Formats date-time for use in a SQL statement.
 	 */
-	public function formatDateTime(/*\DateTimeInterface*/ $value)
+	public function formatDateTime(\DateTimeInterface $value): string
 	{
 		return $value->format("'Y-m-d H:i:s'");
 	}
@@ -104,7 +101,7 @@ public function formatDateTime(/*\DateTimeInterface*/ $value)
 	/**
 	 * Formats date-time interval for use in a SQL statement.
 	 */
-	public function formatDateInterval(\DateInterval $value)
+	public function formatDateInterval(\DateInterval $value): string
 	{
 		return $value->format("'%r%h:%I:%S'");
 	}
@@ -113,7 +110,7 @@ public function formatDateInterval(\DateInterval $value)
 	/**
 	 * Encodes string for use in a LIKE statement.
 	 */
-	public function formatLike($value, $pos)
+	public function formatLike(string $value, int $pos): string
 	{
 		$value = str_replace('\\', '\\\\', $value);
 		$value = addcslashes(substr($this->connection->quote($value), 1, -1), '%_');
@@ -124,7 +121,7 @@ public function formatLike($value, $pos)
 	/**
 	 * Injects LIMIT/OFFSET to the SQL query.
 	 */
-	public function applyLimit(&$sql, $limit, $offset)
+	public function applyLimit(string &$sql, ?int $limit, ?int $offset)
 	{
 		if ($limit < 0 || $offset < 0) {
 			throw new Nette\InvalidArgumentException('Negative offset or limit.');
@@ -140,7 +137,7 @@ public function applyLimit(&$sql, $limit, $offset)
 	/**
 	 * Normalizes result row.
 	 */
-	public function normalizeRow($row)
+	public function normalizeRow(array $row): array
 	{
 		return $row;
 	}
@@ -152,7 +149,7 @@ public function normalizeRow($row)
 	/**
 	 * Returns list of tables.
 	 */
-	public function getTables()
+	public function getTables(): array
 	{
 		$tables = [];
 		foreach ($this->connection->query('SHOW FULL TABLES') as $row) {
@@ -168,7 +165,7 @@ public function getTables()
 	/**
 	 * Returns metadata for all columns in a table.
 	 */
-	public function getColumns($table)
+	public function getColumns(string $table): array
 	{
 		$columns = [];
 		foreach ($this->connection->query('SHOW FULL COLUMNS FROM ' . $this->delimite($table)) as $row) {
@@ -193,7 +190,7 @@ public function getColumns($table)
 	/**
 	 * Returns metadata for all indexes in a table.
 	 */
-	public function getIndexes($table)
+	public function getIndexes(string $table): array
 	{
 		$indexes = [];
 		foreach ($this->connection->query('SHOW INDEX FROM ' . $this->delimite($table)) as $row) {
@@ -209,7 +206,7 @@ public function getIndexes($table)
 	/**
 	 * Returns metadata for all foreign keys in a table.
 	 */
-	public function getForeignKeys($table)
+	public function getForeignKeys(string $table): array
 	{
 		$keys = [];
 		$query = 'SELECT CONSTRAINT_NAME, COLUMN_NAME, REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME FROM information_schema.KEY_COLUMN_USAGE '
@@ -229,7 +226,7 @@ public function getForeignKeys($table)
 	/**
 	 * Returns associative array of detected types (IReflection::FIELD_*) in result set.
 	 */
-	public function getColumnTypes(\PDOStatement $statement)
+	public function getColumnTypes(\PDOStatement $statement): array
 	{
 		$types = [];
 		$count = $statement->columnCount();
@@ -246,11 +243,7 @@ public function getColumnTypes(\PDOStatement $statement)
 	}
 
 
-	/**
-	 * @param  string
-	 * @return bool
-	 */
-	public function isSupported($item)
+	public function isSupported(string $item): bool
 	{
 		// MULTI_COLUMN_AS_OR_COND due to mysql bugs:
 		// - http://bugs.mysql.com/bug.php?id=31188
diff --git a/src/Database/Drivers/OciDriver.php b/src/Database/Drivers/OciDriver.php
index 3630a2a4b..25a4ed4d5 100644
--- a/src/Database/Drivers/OciDriver.php
+++ b/src/Database/Drivers/OciDriver.php
@@ -33,7 +33,7 @@ public function initialize(Nette\Database\Connection $connection, array $options
 	}
 
 
-	public function convertException(\PDOException $e)
+	public function convertException(\PDOException $e): Nette\Database\DriverException
 	{
 		$code = $e->errorInfo[1] ?? NULL;
 		if (in_array($code, [1, 2299, 38911], TRUE)) {
@@ -57,7 +57,7 @@ public function convertException(\PDOException $e)
 	/**
 	 * Delimites identifier for use in a SQL statement.
 	 */
-	public function delimite($name)
+	public function delimite(string $name): string
 	{
 		// @see http://download.oracle.com/docs/cd/B10500_01/server.920/a96540/sql_elements9a.htm
 		return '"' . str_replace('"', '""', $name) . '"';
@@ -67,7 +67,7 @@ public function delimite($name)
 	/**
 	 * Formats boolean for use in a SQL statement.
 	 */
-	public function formatBool($value)
+	public function formatBool(bool $value): string
 	{
 		return $value ? '1' : '0';
 	}
@@ -76,7 +76,7 @@ public function formatBool($value)
 	/**
 	 * Formats date-time for use in a SQL statement.
 	 */
-	public function formatDateTime(/*\DateTimeInterface*/ $value)
+	public function formatDateTime(\DateTimeInterface $value): string
 	{
 		return $value->format($this->fmtDateTime);
 	}
@@ -85,7 +85,7 @@ public function formatDateTime(/*\DateTimeInterface*/ $value)
 	/**
 	 * Formats date-time interval for use in a SQL statement.
 	 */
-	public function formatDateInterval(\DateInterval $value)
+	public function formatDateInterval(\DateInterval $value): string
 	{
 		throw new Nette\NotSupportedException;
 	}
@@ -94,7 +94,7 @@ public function formatDateInterval(\DateInterval $value)
 	/**
 	 * Encodes string for use in a LIKE statement.
 	 */
-	public function formatLike($value, $pos)
+	public function formatLike(string $value, int $pos): string
 	{
 		throw new Nette\NotImplementedException;
 	}
@@ -103,7 +103,7 @@ public function formatLike($value, $pos)
 	/**
 	 * Injects LIMIT/OFFSET to the SQL query.
 	 */
-	public function applyLimit(&$sql, $limit, $offset)
+	public function applyLimit(string &$sql, ?int $limit, ?int $offset)
 	{
 		if ($limit < 0 || $offset < 0) {
 			throw new Nette\InvalidArgumentException('Negative offset or limit.');
@@ -123,7 +123,7 @@ public function applyLimit(&$sql, $limit, $offset)
 	/**
 	 * Normalizes result row.
 	 */
-	public function normalizeRow($row)
+	public function normalizeRow(array $row): array
 	{
 		return $row;
 	}
@@ -135,7 +135,7 @@ public function normalizeRow($row)
 	/**
 	 * Returns list of tables.
 	 */
-	public function getTables()
+	public function getTables(): array
 	{
 		$tables = [];
 		foreach ($this->connection->query('SELECT * FROM cat') as $row) {
@@ -153,7 +153,7 @@ public function getTables()
 	/**
 	 * Returns metadata for all columns in a table.
 	 */
-	public function getColumns($table)
+	public function getColumns(string $table): array
 	{
 		throw new Nette\NotImplementedException;
 	}
@@ -162,7 +162,7 @@ public function getColumns($table)
 	/**
 	 * Returns metadata for all indexes in a table.
 	 */
-	public function getIndexes($table)
+	public function getIndexes(string $table): array
 	{
 		throw new Nette\NotImplementedException;
 	}
@@ -171,7 +171,7 @@ public function getIndexes($table)
 	/**
 	 * Returns metadata for all foreign keys in a table.
 	 */
-	public function getForeignKeys($table)
+	public function getForeignKeys(string $table): array
 	{
 		throw new Nette\NotImplementedException;
 	}
@@ -180,17 +180,13 @@ public function getForeignKeys($table)
 	/**
 	 * Returns associative array of detected types (IReflection::FIELD_*) in result set.
 	 */
-	public function getColumnTypes(\PDOStatement $statement)
+	public function getColumnTypes(\PDOStatement $statement): array
 	{
 		return Nette\Database\Helpers::detectTypes($statement);
 	}
 
 
-	/**
-	 * @param  string
-	 * @return bool
-	 */
-	public function isSupported($item)
+	public function isSupported(string $item): bool
 	{
 		return $item === self::SUPPORT_SEQUENCE || $item === self::SUPPORT_SUBSELECT;
 	}
diff --git a/src/Database/Drivers/OdbcDriver.php b/src/Database/Drivers/OdbcDriver.php
index b6ea602d5..8287ffe27 100644
--- a/src/Database/Drivers/OdbcDriver.php
+++ b/src/Database/Drivers/OdbcDriver.php
@@ -24,7 +24,7 @@ public function initialize(Nette\Database\Connection $connection, array $options
 	}
 
 
-	public function convertException(\PDOException $e)
+	public function convertException(\PDOException $e): Nette\Database\DriverException
 	{
 		return Nette\Database\DriverException::from($e);
 	}
@@ -36,7 +36,7 @@ public function convertException(\PDOException $e)
 	/**
 	 * Delimites identifier for use in a SQL statement.
 	 */
-	public function delimite($name)
+	public function delimite(string $name): string
 	{
 		return '[' . str_replace(['[', ']'], ['[[', ']]'], $name) . ']';
 	}
@@ -45,7 +45,7 @@ public function delimite($name)
 	/**
 	 * Formats boolean for use in a SQL statement.
 	 */
-	public function formatBool($value)
+	public function formatBool(bool $value): string
 	{
 		return $value ? '1' : '0';
 	}
@@ -54,7 +54,7 @@ public function formatBool($value)
 	/**
 	 * Formats date-time for use in a SQL statement.
 	 */
-	public function formatDateTime(/*\DateTimeInterface*/ $value)
+	public function formatDateTime(\DateTimeInterface $value): string
 	{
 		return $value->format('#m/d/Y H:i:s#');
 	}
@@ -63,7 +63,7 @@ public function formatDateTime(/*\DateTimeInterface*/ $value)
 	/**
 	 * Formats date-time interval for use in a SQL statement.
 	 */
-	public function formatDateInterval(\DateInterval $value)
+	public function formatDateInterval(\DateInterval $value): string
 	{
 		throw new Nette\NotSupportedException;
 	}
@@ -72,7 +72,7 @@ public function formatDateInterval(\DateInterval $value)
 	/**
 	 * Encodes string for use in a LIKE statement.
 	 */
-	public function formatLike($value, $pos)
+	public function formatLike(string $value, int $pos): string
 	{
 		$value = strtr($value, ["'" => "''", '%' => '[%]', '_' => '[_]', '[' => '[[]']);
 		return ($pos <= 0 ? "'%" : "'") . $value . ($pos >= 0 ? "%'" : "'");
@@ -82,7 +82,7 @@ public function formatLike($value, $pos)
 	/**
 	 * Injects LIMIT/OFFSET to the SQL query.
 	 */
-	public function applyLimit(&$sql, $limit, $offset)
+	public function applyLimit(string &$sql, ?int $limit, ?int $offset)
 	{
 		if ($offset) {
 			throw new Nette\NotSupportedException('Offset is not supported by this database.');
@@ -102,7 +102,7 @@ public function applyLimit(&$sql, $limit, $offset)
 	/**
 	 * Normalizes result row.
 	 */
-	public function normalizeRow($row)
+	public function normalizeRow(array $row): array
 	{
 		return $row;
 	}
@@ -114,7 +114,7 @@ public function normalizeRow($row)
 	/**
 	 * Returns list of tables.
 	 */
-	public function getTables()
+	public function getTables(): array
 	{
 		throw new Nette\NotImplementedException;
 	}
@@ -123,7 +123,7 @@ public function getTables()
 	/**
 	 * Returns metadata for all columns in a table.
 	 */
-	public function getColumns($table)
+	public function getColumns(string $table): array
 	{
 		throw new Nette\NotImplementedException;
 	}
@@ -132,7 +132,7 @@ public function getColumns($table)
 	/**
 	 * Returns metadata for all indexes in a table.
 	 */
-	public function getIndexes($table)
+	public function getIndexes(string $table): array
 	{
 		throw new Nette\NotImplementedException;
 	}
@@ -141,7 +141,7 @@ public function getIndexes($table)
 	/**
 	 * Returns metadata for all foreign keys in a table.
 	 */
-	public function getForeignKeys($table)
+	public function getForeignKeys(string $table): array
 	{
 		throw new Nette\NotImplementedException;
 	}
@@ -150,17 +150,13 @@ public function getForeignKeys($table)
 	/**
 	 * Returns associative array of detected types (IReflection::FIELD_*) in result set.
 	 */
-	public function getColumnTypes(\PDOStatement $statement)
+	public function getColumnTypes(\PDOStatement $statement): array
 	{
 		return Nette\Database\Helpers::detectTypes($statement);
 	}
 
 
-	/**
-	 * @param  string
-	 * @return bool
-	 */
-	public function isSupported($item)
+	public function isSupported(string $item): bool
 	{
 		return $item === self::SUPPORT_SUBSELECT;
 	}
diff --git a/src/Database/Drivers/PgSqlDriver.php b/src/Database/Drivers/PgSqlDriver.php
index a0351f412..d615a1f3d 100644
--- a/src/Database/Drivers/PgSqlDriver.php
+++ b/src/Database/Drivers/PgSqlDriver.php
@@ -29,7 +29,7 @@ public function initialize(Nette\Database\Connection $connection, array $options
 	}
 
 
-	public function convertException(\PDOException $e)
+	public function convertException(\PDOException $e): Nette\Database\DriverException
 	{
 		$code = $e->errorInfo[0] ?? NULL;
 		if ($code === '0A000' && strpos($e->getMessage(), 'truncate') !== FALSE) {
@@ -59,7 +59,7 @@ public function convertException(\PDOException $e)
 	/**
 	 * Delimites identifier for use in a SQL statement.
 	 */
-	public function delimite($name)
+	public function delimite(string $name): string
 	{
 		// @see http://www.postgresql.org/docs/8.2/static/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS
 		return '"' . str_replace('"', '""', $name) . '"';
@@ -69,7 +69,7 @@ public function delimite($name)
 	/**
 	 * Formats boolean for use in a SQL statement.
 	 */
-	public function formatBool($value)
+	public function formatBool(bool $value): string
 	{
 		return $value ? 'TRUE' : 'FALSE';
 	}
@@ -78,7 +78,7 @@ public function formatBool($value)
 	/**
 	 * Formats date-time for use in a SQL statement.
 	 */
-	public function formatDateTime(/*\DateTimeInterface*/ $value)
+	public function formatDateTime(\DateTimeInterface $value): string
 	{
 		return $value->format("'Y-m-d H:i:s'");
 	}
@@ -87,7 +87,7 @@ public function formatDateTime(/*\DateTimeInterface*/ $value)
 	/**
 	 * Formats date-time interval for use in a SQL statement.
 	 */
-	public function formatDateInterval(\DateInterval $value)
+	public function formatDateInterval(\DateInterval $value): string
 	{
 		throw new Nette\NotSupportedException;
 	}
@@ -96,7 +96,7 @@ public function formatDateInterval(\DateInterval $value)
 	/**
 	 * Encodes string for use in a LIKE statement.
 	 */
-	public function formatLike($value, $pos)
+	public function formatLike(string $value, int $pos): string
 	{
 		$bs = substr($this->connection->quote('\\'), 1, -1); // standard_conforming_strings = on/off
 		$value = substr($this->connection->quote($value), 1, -1);
@@ -108,7 +108,7 @@ public function formatLike($value, $pos)
 	/**
 	 * Injects LIMIT/OFFSET to the SQL query.
 	 */
-	public function applyLimit(&$sql, $limit, $offset)
+	public function applyLimit(string &$sql, ?int $limit, ?int $offset)
 	{
 		if ($limit < 0 || $offset < 0) {
 			throw new Nette\InvalidArgumentException('Negative offset or limit.');
@@ -125,7 +125,7 @@ public function applyLimit(&$sql, $limit, $offset)
 	/**
 	 * Normalizes result row.
 	 */
-	public function normalizeRow($row)
+	public function normalizeRow(array $row): array
 	{
 		return $row;
 	}
@@ -137,7 +137,7 @@ public function normalizeRow($row)
 	/**
 	 * Returns list of tables.
 	 */
-	public function getTables()
+	public function getTables(): array
 	{
 		$tables = [];
 		foreach ($this->connection->query("
@@ -164,7 +164,7 @@ public function getTables()
 	/**
 	 * Returns metadata for all columns in a table.
 	 */
-	public function getColumns($table)
+	public function getColumns(string $table): array
 	{
 		$columns = [];
 		foreach ($this->connection->query("
@@ -207,7 +207,7 @@ public function getColumns($table)
 	/**
 	 * Returns metadata for all indexes in a table.
 	 */
-	public function getIndexes($table)
+	public function getIndexes(string $table): array
 	{
 		$indexes = [];
 		foreach ($this->connection->query("
@@ -238,7 +238,7 @@ public function getIndexes($table)
 	/**
 	 * Returns metadata for all foreign keys in a table.
 	 */
-	public function getForeignKeys($table)
+	public function getForeignKeys(string $table): array
 	{
 		/* Does't work with multicolumn foreign keys */
 		return $this->connection->query("
@@ -265,17 +265,13 @@ public function getForeignKeys($table)
 	/**
 	 * Returns associative array of detected types (IReflection::FIELD_*) in result set.
 	 */
-	public function getColumnTypes(\PDOStatement $statement)
+	public function getColumnTypes(\PDOStatement $statement): array
 	{
 		return Nette\Database\Helpers::detectTypes($statement);
 	}
 
 
-	/**
-	 * @param  string
-	 * @return bool
-	 */
-	public function isSupported($item)
+	public function isSupported(string $item): bool
 	{
 		return $item === self::SUPPORT_SEQUENCE || $item === self::SUPPORT_SUBSELECT || $item === self::SUPPORT_SCHEMA;
 	}
@@ -283,10 +279,8 @@ public function isSupported($item)
 
 	/**
 	 * Converts: schema.name => "schema"."name"
-	 * @param  string
-	 * @return string
 	 */
-	private function delimiteFQN($name)
+	private function delimiteFQN(string $name): string
 	{
 		return implode('.', array_map([$this, 'delimite'], explode('.', $name)));
 	}
diff --git a/src/Database/Drivers/SqliteDriver.php b/src/Database/Drivers/SqliteDriver.php
index 73c8e6025..d2d4ef28f 100644
--- a/src/Database/Drivers/SqliteDriver.php
+++ b/src/Database/Drivers/SqliteDriver.php
@@ -33,7 +33,7 @@ public function initialize(Nette\Database\Connection $connection, array $options
 	}
 
 
-	public function convertException(\PDOException $e)
+	public function convertException(\PDOException $e): Nette\Database\DriverException
 	{
 		$code = $e->errorInfo[1] ?? NULL;
 		$msg = $e->getMessage();
@@ -68,7 +68,7 @@ public function convertException(\PDOException $e)
 	/**
 	 * Delimites identifier for use in a SQL statement.
 	 */
-	public function delimite($name)
+	public function delimite(string $name): string
 	{
 		return '[' . strtr($name, '[]', '  ') . ']';
 	}
@@ -77,7 +77,7 @@ public function delimite($name)
 	/**
 	 * Formats boolean for use in a SQL statement.
 	 */
-	public function formatBool($value)
+	public function formatBool(bool $value): string
 	{
 		return $value ? '1' : '0';
 	}
@@ -86,7 +86,7 @@ public function formatBool($value)
 	/**
 	 * Formats date-time for use in a SQL statement.
 	 */
-	public function formatDateTime(/*\DateTimeInterface*/ $value)
+	public function formatDateTime(\DateTimeInterface $value): string
 	{
 		return $value->format($this->fmtDateTime);
 	}
@@ -95,7 +95,7 @@ public function formatDateTime(/*\DateTimeInterface*/ $value)
 	/**
 	 * Formats date-time interval for use in a SQL statement.
 	 */
-	public function formatDateInterval(\DateInterval $value)
+	public function formatDateInterval(\DateInterval $value): string
 	{
 		throw new Nette\NotSupportedException;
 	}
@@ -104,7 +104,7 @@ public function formatDateInterval(\DateInterval $value)
 	/**
 	 * Encodes string for use in a LIKE statement.
 	 */
-	public function formatLike($value, $pos)
+	public function formatLike(string $value, int $pos): string
 	{
 		$value = addcslashes(substr($this->connection->quote($value), 1, -1), '%_\\');
 		return ($pos <= 0 ? "'%" : "'") . $value . ($pos >= 0 ? "%'" : "'") . " ESCAPE '\\'";
@@ -114,7 +114,7 @@ public function formatLike($value, $pos)
 	/**
 	 * Injects LIMIT/OFFSET to the SQL query.
 	 */
-	public function applyLimit(&$sql, $limit, $offset)
+	public function applyLimit(string &$sql, ?int $limit, ?int $offset)
 	{
 		if ($limit < 0 || $offset < 0) {
 			throw new Nette\InvalidArgumentException('Negative offset or limit.');
@@ -129,7 +129,7 @@ public function applyLimit(&$sql, $limit, $offset)
 	/**
 	 * Normalizes result row.
 	 */
-	public function normalizeRow($row)
+	public function normalizeRow(array $row): array
 	{
 		foreach ($row as $key => $value) {
 			unset($row[$key]);
@@ -148,7 +148,7 @@ public function normalizeRow($row)
 	/**
 	 * Returns list of tables.
 	 */
-	public function getTables()
+	public function getTables(): array
 	{
 		$tables = [];
 		foreach ($this->connection->query("
@@ -170,7 +170,7 @@ public function getTables()
 	/**
 	 * Returns metadata for all columns in a table.
 	 */
-	public function getColumns($table)
+	public function getColumns(string $table): array
 	{
 		$meta = $this->connection->query("
 			SELECT sql FROM sqlite_master WHERE type = 'table' AND name = {$this->connection->quote($table)}
@@ -203,7 +203,7 @@ public function getColumns($table)
 	/**
 	 * Returns metadata for all indexes in a table.
 	 */
-	public function getIndexes($table)
+	public function getIndexes(string $table): array
 	{
 		$indexes = [];
 		foreach ($this->connection->query("PRAGMA index_list({$this->delimite($table)})") as $row) {
@@ -250,7 +250,7 @@ public function getIndexes($table)
 	/**
 	 * Returns metadata for all foreign keys in a table.
 	 */
-	public function getForeignKeys($table)
+	public function getForeignKeys(string $table): array
 	{
 		$keys = [];
 		foreach ($this->connection->query("PRAGMA foreign_key_list({$this->delimite($table)})") as $row) {
@@ -272,7 +272,7 @@ public function getForeignKeys($table)
 	/**
 	 * Returns associative array of detected types (IReflection::FIELD_*) in result set.
 	 */
-	public function getColumnTypes(\PDOStatement $statement)
+	public function getColumnTypes(\PDOStatement $statement): array
 	{
 		$types = [];
 		$count = $statement->columnCount();
@@ -292,11 +292,7 @@ public function getColumnTypes(\PDOStatement $statement)
 	}
 
 
-	/**
-	 * @param  string
-	 * @return bool
-	 */
-	public function isSupported($item)
+	public function isSupported(string $item): bool
 	{
 		return $item === self::SUPPORT_MULTI_INSERT_AS_SELECT || $item === self::SUPPORT_SUBSELECT || $item === self::SUPPORT_MULTI_COLUMN_AS_OR_COND;
 	}
diff --git a/src/Database/Drivers/SqlsrvDriver.php b/src/Database/Drivers/SqlsrvDriver.php
index 05d4a2ae1..3839a841e 100644
--- a/src/Database/Drivers/SqlsrvDriver.php
+++ b/src/Database/Drivers/SqlsrvDriver.php
@@ -33,7 +33,7 @@ public function initialize(Nette\Database\Connection $connection, array $options
 	}
 
 
-	public function convertException(\PDOException $e)
+	public function convertException(\PDOException $e): Nette\Database\DriverException
 	{
 		return Nette\Database\DriverException::from($e);
 	}
@@ -45,7 +45,7 @@ public function convertException(\PDOException $e)
 	/**
 	 * Delimites identifier for use in a SQL statement.
 	 */
-	public function delimite($name)
+	public function delimite(string $name): string
 	{
 		/** @see https://msdn.microsoft.com/en-us/library/ms176027.aspx */
 		return '[' . str_replace(']', ']]', $name) . ']';
@@ -55,7 +55,7 @@ public function delimite($name)
 	/**
 	 * Formats boolean for use in a SQL statement.
 	 */
-	public function formatBool($value)
+	public function formatBool(bool $value): string
 	{
 		return $value ? '1' : '0';
 	}
@@ -64,7 +64,7 @@ public function formatBool($value)
 	/**
 	 * Formats date-time for use in a SQL statement.
 	 */
-	public function formatDateTime(/*\DateTimeInterface*/ $value)
+	public function formatDateTime(\DateTimeInterface $value): string
 	{
 		/** @see https://msdn.microsoft.com/en-us/library/ms187819.aspx */
 		return $value->format("'Y-m-d\\TH:i:s'");
@@ -74,7 +74,7 @@ public function formatDateTime(/*\DateTimeInterface*/ $value)
 	/**
 	 * Formats date-time interval for use in a SQL statement.
 	 */
-	public function formatDateInterval(\DateInterval $value)
+	public function formatDateInterval(\DateInterval $value): string
 	{
 		throw new Nette\NotSupportedException;
 	}
@@ -83,7 +83,7 @@ public function formatDateInterval(\DateInterval $value)
 	/**
 	 * Encodes string for use in a LIKE statement.
 	 */
-	public function formatLike($value, $pos)
+	public function formatLike(string $value, int $pos): string
 	{
 		/** @see https://msdn.microsoft.com/en-us/library/ms179859.aspx */
 		$value = strtr($value, ["'" => "''", '%' => '[%]', '_' => '[_]', '[' => '[[]']);
@@ -94,7 +94,7 @@ public function formatLike($value, $pos)
 	/**
 	 * Injects LIMIT/OFFSET to the SQL query.
 	 */
-	public function applyLimit(&$sql, $limit, $offset)
+	public function applyLimit(string &$sql, ?int $limit, ?int $offset)
 	{
 		if ($limit < 0 || $offset < 0) {
 			throw new Nette\InvalidArgumentException('Negative offset or limit.');
@@ -121,7 +121,7 @@ public function applyLimit(&$sql, $limit, $offset)
 	/**
 	 * Normalizes result row.
 	 */
-	public function normalizeRow($row)
+	public function normalizeRow(array $row): array
 	{
 		return $row;
 	}
@@ -133,7 +133,7 @@ public function normalizeRow($row)
 	/**
 	 * Returns list of tables.
 	 */
-	public function getTables()
+	public function getTables(): array
 	{
 		$tables = [];
 		foreach ($this->connection->query("
@@ -161,7 +161,7 @@ public function getTables()
 	/**
 	 * Returns metadata for all columns in a table.
 	 */
-	public function getColumns($table)
+	public function getColumns(string $table): array
 	{
 		$columns = [];
 		foreach ($this->connection->query("
@@ -205,7 +205,7 @@ public function getColumns($table)
 	/**
 	 * Returns metadata for all indexes in a table.
 	 */
-	public function getIndexes($table)
+	public function getIndexes(string $table): array
 	{
 		$indexes = [];
 		foreach ($this->connection->query("
@@ -241,7 +241,7 @@ public function getIndexes($table)
 	/**
 	 * Returns metadata for all foreign keys in a table.
 	 */
-	public function getForeignKeys($table)
+	public function getForeignKeys(string $table): array
 	{
 		// Does't work with multicolumn foreign keys
 		$keys = [];
@@ -271,7 +271,7 @@ public function getForeignKeys($table)
 	/**
 	 * Returns associative array of detected types (IReflection::FIELD_*) in result set.
 	 */
-	public function getColumnTypes(\PDOStatement $statement)
+	public function getColumnTypes(\PDOStatement $statement): array
 	{
 		$types = [];
 		$count = $statement->columnCount();
@@ -287,11 +287,7 @@ public function getColumnTypes(\PDOStatement $statement)
 	}
 
 
-	/**
-	 * @param  string
-	 * @return bool
-	 */
-	public function isSupported($item)
+	public function isSupported(string $item): bool
 	{
 		return $item === self::SUPPORT_SUBSELECT;
 	}
diff --git a/src/Database/Helpers.php b/src/Database/Helpers.php
index ab1beca4b..f5b28a2db 100644
--- a/src/Database/Helpers.php
+++ b/src/Database/Helpers.php
@@ -38,9 +38,8 @@ class Helpers
 
 	/**
 	 * Displays complete result set as HTML table for debug purposes.
-	 * @return void
 	 */
-	public static function dumpResult(ResultSet $result)
+	public static function dumpResult(ResultSet $result): void
 	{
 		echo "\n<table class=\"dump\">\n<caption>" . htmlSpecialChars($result->getQueryString(), ENT_IGNORE, 'UTF-8') . "</caption>\n";
 		if (!$result->getColumnCount()) {
@@ -74,10 +73,8 @@ public static function dumpResult(ResultSet $result)
 
 	/**
 	 * Returns syntax highlighted SQL command.
-	 * @param  string
-	 * @return string
 	 */
-	public static function dumpSql($sql, array $params = NULL, Connection $connection = NULL)
+	public static function dumpSql(string $sql, array $params = NULL, Connection $connection = NULL): string
 	{
 		static $keywords1 = 'SELECT|(?:ON\s+DUPLICATE\s+KEY)?UPDATE|INSERT(?:\s+INTO)?|REPLACE(?:\s+INTO)?|DELETE|CALL|UNION|FROM|WHERE|HAVING|GROUP\s+BY|ORDER\s+BY|LIMIT|OFFSET|SET|VALUES|LEFT\s+JOIN|INNER\s+JOIN|TRUNCATE';
 		static $keywords2 = 'ALL|DISTINCT|DISTINCTROW|IGNORE|AS|USING|ON|AND|OR|IN|IS|NOT|NULL|[RI]?LIKE|REGEXP|TRUE|FALSE';
@@ -144,9 +141,8 @@ public static function dumpSql($sql, array $params = NULL, Connection $connectio
 
 	/**
 	 * Common column type detection.
-	 * @return array
 	 */
-	public static function detectTypes(\PDOStatement $statement)
+	public static function detectTypes(\PDOStatement $statement): array
 	{
 		$types = [];
 		$count = $statement->columnCount(); // driver must be meta-aware, see PHP bugs #53782, #54695
@@ -162,11 +158,9 @@ public static function detectTypes(\PDOStatement $statement)
 
 	/**
 	 * Heuristic column type detection.
-	 * @param  string
-	 * @return string
 	 * @internal
 	 */
-	public static function detectType($type)
+	public static function detectType(string $type): string
 	{
 		static $cache;
 		if (!isset($cache[$type])) {
@@ -185,7 +179,7 @@ public static function detectType($type)
 	 * Import SQL dump from file - extremely fast.
 	 * @return int  count of commands
 	 */
-	public static function loadFromFile(Connection $connection, $file)
+	public static function loadFromFile(Connection $connection, $file): int
 	{
 		@set_time_limit(0); // @ function may be disabled
 
@@ -222,7 +216,7 @@ public static function loadFromFile(Connection $connection, $file)
 	}
 
 
-	public static function createDebugPanel($connection, $explain = TRUE, $name = NULL)
+	public static function createDebugPanel($connection, bool $explain = TRUE, $name = NULL)
 	{
 		$panel = new Nette\Bridges\DatabaseTracy\ConnectionPanel($connection);
 		$panel->explain = $explain;
@@ -234,9 +228,8 @@ public static function createDebugPanel($connection, $explain = TRUE, $name = NU
 
 	/**
 	 * Reformat source to key -> value pairs.
-	 * @return array
 	 */
-	public static function toPairs(array $rows, $key = NULL, $value = NULL)
+	public static function toPairs(array $rows, $key = NULL, $value = NULL): array
 	{
 		if (!$rows) {
 			return [];
@@ -271,10 +264,8 @@ public static function toPairs(array $rows, $key = NULL, $value = NULL)
 
 	/**
 	 * Finds duplicate columns in select statement
-	 * @param  \PDOStatement
-	 * @return string
 	 */
-	public static function findDuplicates(\PDOStatement $statement)
+	public static function findDuplicates(\PDOStatement $statement): string
 	{
 		$cols = [];
 		for ($i = 0; $i < $statement->columnCount(); $i++) {
diff --git a/src/Database/IConventions.php b/src/Database/IConventions.php
index a4a77c00b..3c13f9807 100644
--- a/src/Database/IConventions.php
+++ b/src/Database/IConventions.php
@@ -17,10 +17,9 @@ interface IConventions
 
 	/**
 	 * Returns primary key for table.
-	 * @param  string
 	 * @return string|array|NULL
 	 */
-	function getPrimary($table);
+	function getPrimary(string $table);
 
 	/**
 	 * Returns referenced table & referenced column.
@@ -32,7 +31,7 @@ function getPrimary($table);
 	 * @return array|NULL   array(referenced table, referenced column)
 	 * @throws AmbiguousReferenceKeyException
 	 */
-	function getHasManyReference($table, $key);
+	function getHasManyReference(string $table, string $key): ?array;
 
 	/**
 	 * Returns referenced table & referencing column.
@@ -44,6 +43,6 @@ function getHasManyReference($table, $key);
 	 * @param  string  referencing key
 	 * @return array|NULL   array(referenced table, referencing column)
 	 */
-	function getBelongsToReference($table, $key);
+	function getBelongsToReference(string $table, string $key): ?array;
 
 }
diff --git a/src/Database/IRowContainer.php b/src/Database/IRowContainer.php
index 9eb0b483f..48a07aaee 100644
--- a/src/Database/IRowContainer.php
+++ b/src/Database/IRowContainer.php
@@ -18,9 +18,8 @@ interface IRowContainer extends \Traversable
 
 	/**
 	 * Fetches single row object.
-	 * @return IRow|NULL if there is no row
 	 */
-	function fetch();
+	function fetch(): ?IRow;
 
 	/**
 	 * Fetches single field.
@@ -33,21 +32,19 @@ function fetchField($column = 0);
 	 * Fetches all rows as associative array.
 	 * @param  string|int column name used for an array key or NULL for numeric index
 	 * @param  string|int column name used for an array value or NULL for the whole row
-	 * @return array
 	 */
-	function fetchPairs($key = NULL, $value = NULL);
+	function fetchPairs($key = NULL, $value = NULL): array;
 
 	/**
 	 * Fetches all rows.
 	 * @return IRow[]
 	 */
-	function fetchAll();
+	function fetchAll(): array;
 
 	/**
 	 * Fetches all rows and returns associative tree.
 	 * @param  string  associative descriptor
-	 * @return array
 	 */
-	function fetchAssoc($path);
+	function fetchAssoc(string $path): array;
 
 }
diff --git a/src/Database/IStructure.php b/src/Database/IStructure.php
index fc34eeede..4a1e89a5d 100644
--- a/src/Database/IStructure.php
+++ b/src/Database/IStructure.php
@@ -29,48 +29,36 @@ interface IStructure
 
 	/**
 	 * Returns tables list.
-	 * @return array
 	 */
-	function getTables();
+	function getTables(): array;
 
 	/**
 	 * Returns table columns list.
-	 * @param  string
-	 * @return array
 	 */
-	function getColumns($table);
+	function getColumns(string $table): array;
 
 	/**
 	 * Returns table primary key.
-	 * @param  string
 	 * @return string|array|NULL
 	 */
-	function getPrimaryKey($table);
+	function getPrimaryKey(string $table);
 
 	/**
 	 * Returns table primary key sequence.
-	 * @param  string
-	 * @return string|NULL
 	 */
-	function getPrimaryKeySequence($table);
+	function getPrimaryKeySequence(string $table): ?string;
 
 	/**
 	 * Returns hasMany reference.
 	 * If a targetTable is not provided, returns references for all tables.
-	 * @param  string
-	 * @param  string|NULL
-	 * @return array|NULL
 	 */
-	function getHasManyReference($table, $targetTable = NULL);
+	function getHasManyReference(string $table, string $targetTable = NULL): ?array;
 
 	/**
 	 * Returns belongsTo reference.
 	 * If a column is not provided, returns references for all columns.
-	 * @param  string
-	 * @param  string|NULL
-	 * @return array|NULL
 	 */
-	function getBelongsToReference($table, $column = NULL);
+	function getBelongsToReference(string $table, string $column = NULL): ?array;
 
 	/**
 	 * Rebuilds database structure cache.
@@ -80,8 +68,7 @@ function rebuild();
 
 	/**
 	 * Returns true if database cached structure has been rebuilt.
-	 * @return bool
 	 */
-	function isRebuilt();
+	function isRebuilt(): bool;
 
 }
diff --git a/src/Database/ISupplementalDriver.php b/src/Database/ISupplementalDriver.php
index 12b8a43c5..18c863202 100644
--- a/src/Database/ISupplementalDriver.php
+++ b/src/Database/ISupplementalDriver.php
@@ -24,64 +24,46 @@ interface ISupplementalDriver
 
 	/**
 	 * Initializes connection.
-	 * @return void
 	 */
 	function initialize(Connection $connection, array $options);
 
-	/**
-	 * @return DriverException
-	 */
-	function convertException(\PDOException $e);
+	function convertException(\PDOException $e): DriverException;
 
 	/**
 	 * Delimites identifier for use in a SQL statement.
-	 * @param  string
-	 * @return string
 	 */
-	function delimite($name);
+	function delimite(string $name): string;
 
 	/**
 	 * Formats boolean for use in a SQL statement.
-	 * @param  bool
-	 * @return string
 	 */
-	function formatBool($value);
+	function formatBool(bool $value): string;
 
 	/**
 	 * Formats date-time for use in a SQL statement.
-	 * @return string
 	 */
-	function formatDateTime(/*\DateTimeInterface*/ $value);
+	function formatDateTime(\DateTimeInterface $value): string;
 
 	/**
 	 * Formats date-time interval for use in a SQL statement.
-	 * @return string
 	 */
-	function formatDateInterval(\DateInterval $value);
+	function formatDateInterval(\DateInterval $value): string;
 
 	/**
 	 * Encodes string for use in a LIKE statement.
-	 * @param  string
-	 * @param  int
-	 * @return string
 	 */
-	function formatLike($value, $pos);
+	function formatLike(string $value, int $pos): string;
 
 	/**
 	 * Injects LIMIT/OFFSET to the SQL query.
 	 * @param  string  SQL query that will be modified.
-	 * @param  int|NULL
-	 * @param  int|NULL
-	 * @return void
 	 */
-	function applyLimit(&$sql, $limit, $offset);
+	function applyLimit(string &$sql, ?int $limit, ?int $offset);
 
 	/**
 	 * Normalizes result row.
-	 * @param  array
-	 * @return array
 	 */
-	function normalizeRow($row);
+	function normalizeRow(array $row): array;
 
 
 	/********************* reflection ****************d*g**/
@@ -91,41 +73,34 @@ function normalizeRow($row);
 	 * Returns list of tables.
 	 * @return array of [name [, (bool) view]]
 	 */
-	function getTables();
+	function getTables(): array;
 
 	/**
 	 * Returns metadata for all columns in a table.
-	 * @param  string
 	 * @return array of [name, nativetype, primary [, table, fullname, (int) size, (bool) nullable, (mixed) default, (bool) autoincrement, (array) vendor]]
 	 */
-	function getColumns($table);
+	function getColumns(string $table): array;
 
 	/**
 	 * Returns metadata for all indexes in a table.
-	 * @param  string
 	 * @return array of [name, (array of names) columns [, (bool) unique, (bool) primary]]
 	 */
-	function getIndexes($table);
+	function getIndexes(string $table): array;
 
 	/**
 	 * Returns metadata for all foreign keys in a table.
-	 * @param  string
-	 * @return array
 	 */
-	function getForeignKeys($table);
+	function getForeignKeys(string $table): array;
 
 	/**
 	 * Returns associative array of detected types (IStructure::FIELD_*) in result set.
-	 * @param  \PDOStatement
-	 * @return array
 	 */
-	function getColumnTypes(\PDOStatement $statement);
+	function getColumnTypes(\PDOStatement $statement): array;
 
 	/**
 	 * Cheks if driver supports specific property
 	 * @param  string self::SUPPORT_* property
-	 * @return bool
 	 */
-	function isSupported($item);
+	function isSupported(string $item): bool;
 
 }
diff --git a/src/Database/ResultSet.php b/src/Database/ResultSet.php
index 607460d6d..975885dba 100644
--- a/src/Database/ResultSet.php
+++ b/src/Database/ResultSet.php
@@ -82,10 +82,7 @@ public function __construct(Connection $connection, $queryString, array $params)
 	}
 
 
-	/**
-	 * @return Connection
-	 */
-	public function getConnection()
+	public function getConnection(): Connection
 	{
 		return $this->connection;
 	}
@@ -93,54 +90,38 @@ public function getConnection()
 
 	/**
 	 * @internal
-	 * @return \PDOStatement
 	 */
-	public function getPdoStatement()
+	public function getPdoStatement(): \PDOStatement
 	{
 		return $this->pdoStatement;
 	}
 
 
-	/**
-	 * @return string
-	 */
-	public function getQueryString()
+	public function getQueryString(): string
 	{
 		return $this->queryString;
 	}
 
 
-	/**
-	 * @return array
-	 */
-	public function getParameters()
+	public function getParameters(): array
 	{
 		return $this->params;
 	}
 
 
-	/**
-	 * @return int
-	 */
-	public function getColumnCount()
+	public function getColumnCount(): ?int
 	{
 		return $this->pdoStatement ? $this->pdoStatement->columnCount() : NULL;
 	}
 
 
-	/**
-	 * @return int
-	 */
-	public function getRowCount()
+	public function getRowCount(): ?int
 	{
 		return $this->pdoStatement ? $this->pdoStatement->rowCount() : NULL;
 	}
 
 
-	/**
-	 * @return float
-	 */
-	public function getTime()
+	public function getTime(): float
 	{
 		return $this->time;
 	}
@@ -148,10 +129,8 @@ public function getTime()
 
 	/**
 	 * Normalizes result row.
-	 * @param  array
-	 * @return array
 	 */
-	public function normalizeRow($row)
+	public function normalizeRow(array $row): array
 	{
 		if ($this->types === NULL) {
 			$this->types = (array) $this->supplementalDriver->getColumnTypes($this->pdoStatement);
@@ -196,9 +175,8 @@ public function normalizeRow($row)
 
 	/**
 	 * Displays complete result set as HTML table for debug purposes.
-	 * @return void
 	 */
-	public function dump()
+	public function dump(): void
 	{
 		Helpers::dumpResult($this);
 	}
@@ -249,7 +227,7 @@ public function valid()
 	/**
 	 * @inheritDoc
 	 */
-	public function fetch()
+	public function fetch(): ?IRow
 	{
 		$data = $this->pdoStatement ? $this->pdoStatement->fetch() : NULL;
 		if (!$data) {
@@ -286,7 +264,7 @@ public function fetchField($column = 0)
 	/**
 	 * @inheritDoc
 	 */
-	public function fetchPairs($key = NULL, $value = NULL)
+	public function fetchPairs($key = NULL, $value = NULL): array
 	{
 		return Helpers::toPairs($this->fetchAll(), $key, $value);
 	}
@@ -295,7 +273,7 @@ public function fetchPairs($key = NULL, $value = NULL)
 	/**
 	 * @inheritDoc
 	 */
-	public function fetchAll()
+	public function fetchAll(): array
 	{
 		if ($this->results === NULL) {
 			$this->results = iterator_to_array($this);
@@ -307,7 +285,7 @@ public function fetchAll()
 	/**
 	 * @inheritDoc
 	 */
-	public function fetchAssoc($path)
+	public function fetchAssoc(string $path): array
 	{
 		return Nette\Utils\Arrays::associate($this->fetchAll(), $path);
 	}
diff --git a/src/Database/Row.php b/src/Database/Row.php
index 90ea649bf..6e477061c 100644
--- a/src/Database/Row.php
+++ b/src/Database/Row.php
@@ -46,9 +46,8 @@ public function offsetGet($key)
 	/**
 	 * Checks if $key exists.
 	 * @param  mixed  key or index
-	 * @return bool
 	 */
-	public function offsetExists($key)
+	public function offsetExists($key): bool
 	{
 		if (is_int($key)) {
 			return (bool) current(array_slice((array) $this, $key, 1));
diff --git a/src/Database/SqlLiteral.php b/src/Database/SqlLiteral.php
index 9fa4f090b..48a29a2d1 100644
--- a/src/Database/SqlLiteral.php
+++ b/src/Database/SqlLiteral.php
@@ -26,26 +26,20 @@ class SqlLiteral
 	private $parameters;
 
 
-	public function __construct($value, array $parameters = [])
+	public function __construct(string $value, array $parameters = [])
 	{
 		$this->value = (string) $value;
 		$this->parameters = $parameters;
 	}
 
 
-	/**
-	 * @return array
-	 */
-	public function getParameters()
+	public function getParameters(): array
 	{
 		return $this->parameters;
 	}
 
 
-	/**
-	 * @return string
-	 */
-	public function __toString()
+	public function __toString(): string
 	{
 		return $this->value;
 	}
diff --git a/src/Database/SqlPreprocessor.php b/src/Database/SqlPreprocessor.php
index f3d7c0038..aa60beef4 100644
--- a/src/Database/SqlPreprocessor.php
+++ b/src/Database/SqlPreprocessor.php
@@ -46,10 +46,9 @@ public function __construct(Connection $connection)
 
 
 	/**
-	 * @param  array
 	 * @return array of [sql, params]
 	 */
-	public function process($params)
+	public function process(array $params): array
 	{
 		$this->params = $params;
 		$this->counter = 0;
@@ -258,7 +257,7 @@ private function formatValue($value, $mode = NULL)
 	}
 
 
-	private function delimite($name)
+	private function delimite(string $name): string
 	{
 		return implode('.', array_map([$this->driver, 'delimite'], explode('.', $name)));
 	}
diff --git a/src/Database/Structure.php b/src/Database/Structure.php
index e627267cd..e71c33843 100644
--- a/src/Database/Structure.php
+++ b/src/Database/Structure.php
@@ -39,14 +39,14 @@ public function __construct(Connection $connection, Nette\Caching\IStorage $cach
 	}
 
 
-	public function getTables()
+	public function getTables(): array
 	{
 		$this->needStructure();
 		return $this->structure['tables'];
 	}
 
 
-	public function getColumns($table)
+	public function getColumns(string $table): array
 	{
 		$this->needStructure();
 		$table = $this->resolveFQTableName($table);
@@ -55,7 +55,7 @@ public function getColumns($table)
 	}
 
 
-	public function getPrimaryKey($table)
+	public function getPrimaryKey(string $table)
 	{
 		$this->needStructure();
 		$table = $this->resolveFQTableName($table);
@@ -68,7 +68,7 @@ public function getPrimaryKey($table)
 	}
 
 
-	public function getPrimaryKeySequence($table)
+	public function getPrimaryKeySequence(string $table): ?string
 	{
 		$this->needStructure();
 		$table = $this->resolveFQTableName($table);
@@ -92,7 +92,7 @@ public function getPrimaryKeySequence($table)
 	}
 
 
-	public function getHasManyReference($table, $targetTable = NULL)
+	public function getHasManyReference(string $table, string $targetTable = NULL): ?array
 	{
 		$this->needStructure();
 		$table = $this->resolveFQTableName($table);
@@ -116,7 +116,7 @@ public function getHasManyReference($table, $targetTable = NULL)
 	}
 
 
-	public function getBelongsToReference($table, $column = NULL)
+	public function getBelongsToReference(string $table, string $column = NULL): ?array
 	{
 		$this->needStructure();
 		$table = $this->resolveFQTableName($table);
@@ -144,7 +144,7 @@ public function rebuild()
 	}
 
 
-	public function isRebuilt()
+	public function isRebuilt(): bool
 	{
 		return $this->isRebuilt;
 	}
@@ -219,7 +219,7 @@ protected function analyzePrimaryKey(array $columns)
 	}
 
 
-	protected function analyzeForeignKeys(&$structure, $table)
+	protected function analyzeForeignKeys(&$structure, string $table)
 	{
 		$lowerTable = strtolower($table);
 		foreach ($this->connection->getSupplementalDriver()->getForeignKeys($table) as $row) {
@@ -235,7 +235,7 @@ protected function analyzeForeignKeys(&$structure, $table)
 	}
 
 
-	protected function resolveFQTableName($table)
+	protected function resolveFQTableName(string $table)
 	{
 		$name = strtolower($table);
 		if (isset($this->structure['columns'][$name])) {
diff --git a/src/Database/Table/ActiveRow.php b/src/Database/Table/ActiveRow.php
index 04e747b09..ac8f3c39d 100644
--- a/src/Database/Table/ActiveRow.php
+++ b/src/Database/Table/ActiveRow.php
@@ -47,7 +47,7 @@ public function setTable(Selection $table)
 	/**
 	 * @internal
 	 */
-	public function getTable()
+	public function getTable(): Selection
 	{
 		return $this->table;
 	}
@@ -66,10 +66,7 @@ public function __toString()
 	}
 
 
-	/**
-	 * @return array
-	 */
-	public function toArray()
+	public function toArray(): array
 	{
 		$this->accessColumn(NULL);
 		return $this->data;
@@ -78,10 +75,9 @@ public function toArray()
 
 	/**
 	 * Returns primary key value.
-	 * @param  bool
 	 * @return mixed possible int, string, array, object (Nette\Utils\DateTime)
 	 */
-	public function getPrimary($throw = TRUE)
+	public function getPrimary(bool $throw = TRUE)
 	{
 		$primary = $this->table->getPrimary($throw);
 		if ($primary === NULL) {
@@ -115,10 +111,8 @@ public function getPrimary($throw = TRUE)
 
 	/**
 	 * Returns row signature (composition of primary keys)
-	 * @param  bool
-	 * @return string
 	 */
-	public function getSignature($throw = TRUE)
+	public function getSignature(bool $throw = TRUE): string
 	{
 		return implode('|', (array) $this->getPrimary($throw));
 	}
@@ -126,11 +120,9 @@ public function getSignature($throw = TRUE)
 
 	/**
 	 * Returns referenced row.
-	 * @param  string
-	 * @param  string
 	 * @return IRow|NULL if the row does not exist
 	 */
-	public function ref($key, $throughColumn = NULL)
+	public function ref(string $key, string $throughColumn = NULL): ?IRow
 	{
 		$row = $this->table->getReferencedTable($this, $key, $throughColumn);
 		if ($row === FALSE) {
@@ -143,11 +135,8 @@ public function ref($key, $throughColumn = NULL)
 
 	/**
 	 * Returns referencing rows.
-	 * @param  string
-	 * @param  string
-	 * @return GroupedSelection
 	 */
-	public function related($key, $throughColumn = NULL)
+	public function related(string $key, string $throughColumn = NULL): GroupedSelection
 	{
 		$groupedSelection = $this->table->getReferencingTable($key, $throughColumn, $this[$this->table->getPrimary()]);
 		if (!$groupedSelection) {
@@ -160,10 +149,8 @@ public function related($key, $throughColumn = NULL)
 
 	/**
 	 * Updates row.
-	 * @param  iterable (column => value)
-	 * @return bool
 	 */
-	public function update($data)
+	public function update(iterable $data): bool
 	{
 		if ($data instanceof \Traversable) {
 			$data = iterator_to_array($data);
@@ -198,7 +185,7 @@ public function update($data)
 	 * Deletes row.
 	 * @return int number of affected rows
 	 */
-	public function delete()
+	public function delete(): int
 	{
 		$res = $this->table->createSelectionInstance()
 			->wherePrimary($this->getPrimary())
@@ -229,9 +216,8 @@ public function getIterator()
 	 * Stores value in column.
 	 * @param  string
 	 * @param  mixed
-	 * @return void
 	 */
-	public function offsetSet($column, $value)
+	public function offsetSet($column, $value): void
 	{
 		$this->__set($column, $value);
 	}
@@ -251,9 +237,8 @@ public function offsetGet($column)
 	/**
 	 * Tests if column exists.
 	 * @param  string
-	 * @return bool
 	 */
-	public function offsetExists($column)
+	public function offsetExists($column): bool
 	{
 		return $this->__isset($column);
 	}
@@ -262,9 +247,8 @@ public function offsetExists($column)
 	/**
 	 * Removes column from data.
 	 * @param  string
-	 * @return void
 	 */
-	public function offsetUnset($column)
+	public function offsetUnset($column): void
 	{
 		$this->__unset($column);
 	}
@@ -277,11 +261,10 @@ public function __set($column, $value)
 
 
 	/**
-	 * @param  string
 	 * @return ActiveRow|mixed
 	 * @throws Nette\MemberAccessException
 	 */
-	public function &__get($key)
+	public function &__get(string $key)
 	{
 		if ($this->accessColumn($key)) {
 			return $this->data[$key];
@@ -318,7 +301,7 @@ public function __unset($key)
 	/**
 	 * @internal
 	 */
-	public function accessColumn($key, $selectColumn = TRUE)
+	public function accessColumn($key, bool $selectColumn = TRUE)
 	{
 		if ($this->table->accessColumn($key, $selectColumn) && !$this->dataRefreshed) {
 			if (!isset($this->table[$this->getSignature()])) {
diff --git a/src/Database/Table/GroupedSelection.php b/src/Database/Table/GroupedSelection.php
index e6eee30dc..fa12b077e 100644
--- a/src/Database/Table/GroupedSelection.php
+++ b/src/Database/Table/GroupedSelection.php
@@ -35,14 +35,10 @@ class GroupedSelection extends Selection
 
 	/**
 	 * Creates filtered and grouped table representation.
-	 * @param  Context
-	 * @param  IConventions
-	 * @param  string  database table name
-	 * @param  string  joining column
-	 * @param  Selection
-	 * @param  Nette\Caching\IStorage|NULL
+	 * @param  string $tableName  database table name
+	 * @param  string $column  joining column
 	 */
-	public function __construct(Context $context, IConventions $conventions, $tableName, $column, Selection $refTable, Nette\Caching\IStorage $cacheStorage = NULL)
+	public function __construct(Context $context, IConventions $conventions, string $tableName, string $column, Selection $refTable, Nette\Caching\IStorage $cacheStorage = NULL)
 	{
 		$this->refTable = $refTable;
 		$this->column = $column;
@@ -56,7 +52,7 @@ public function __construct(Context $context, IConventions $conventions, $tableN
 	 * @param  int  primary key of grouped rows
 	 * @return static
 	 */
-	public function setActive($active)
+	public function setActive(int $active)
 	{
 		$this->active = $active;
 		return $this;
@@ -79,7 +75,7 @@ public function select($columns, ...$params)
 	/**
 	 * @return static
 	 */
-	public function order($columns, ...$params)
+	public function order(string $columns, ...$params)
 	{
 		if (!$this->sqlBuilder->getOrder()) {
 			// improve index utilization
@@ -93,7 +89,7 @@ public function order($columns, ...$params)
 	/********************* aggregations ****************d*g**/
 
 
-	public function aggregation($function)
+	public function aggregation(string $function): int
 	{
 		$aggregation = &$this->getRefTable($refPath)->aggregation[$refPath . $function . $this->sqlBuilder->getSelectQueryHash($this->getPreviousAccessedColumns())];
 
@@ -116,13 +112,11 @@ public function aggregation($function)
 				return $val;
 			}
 		}
+		return 0;
 	}
 
 
-	/**
-	 * @return int
-	 */
-	public function count($column = NULL)
+	public function count(string $column = NULL): int
 	{
 		$return = parent::count($column);
 		return $return ?? 0;
@@ -132,7 +126,7 @@ public function count($column = NULL)
 	/********************* internal ****************d*g**/
 
 
-	protected function execute()
+	protected function execute(): void
 	{
 		if ($this->rows !== NULL) {
 			$this->observeCache = $this;
@@ -184,10 +178,7 @@ protected function execute()
 	}
 
 
-	/**
-	 * @return Selection
-	 */
-	protected function getRefTable(&$refPath)
+	protected function getRefTable(&$refPath): Selection
 	{
 		$refObj = $this->refTable;
 		$refPath = $this->name . '.';
@@ -200,7 +191,7 @@ protected function getRefTable(&$refPath)
 	}
 
 
-	protected function loadRefCache()
+	protected function loadRefCache(): void
 	{
 		$hash = $this->getSpecificCacheKey();
 		$referencing = &$this->refCache['referencing'][$this->getGeneralCacheKey()];
@@ -216,7 +207,7 @@ protected function loadRefCache()
 	}
 
 
-	protected function emptyResultSet($saveCache = TRUE, $deleteRererencedCache = TRUE)
+	protected function emptyResultSet(bool $saveCache = TRUE, bool $deleteRererencedCache = TRUE): void
 	{
 		parent::emptyResultSet($saveCache, FALSE);
 	}
@@ -243,7 +234,7 @@ public function insert($data)
 	}
 
 
-	public function update($data)
+	public function update(iterable $data): int
 	{
 		$builder = $this->sqlBuilder;
 
@@ -256,7 +247,7 @@ public function update($data)
 	}
 
 
-	public function delete()
+	public function delete(): int
 	{
 		$builder = $this->sqlBuilder;
 
diff --git a/src/Database/Table/IRow.php b/src/Database/Table/IRow.php
index e031f741e..9ebdd5110 100644
--- a/src/Database/Table/IRow.php
+++ b/src/Database/Table/IRow.php
@@ -20,39 +20,28 @@ interface IRow extends Database\IRow
 
 	function setTable(Selection $name);
 
-	/**
-	 * @return Selection
-	 */
-	function getTable();
+	function getTable(): Selection;
 
 	/**
 	 * Returns primary key value.
-	 * @param  bool
 	 * @return mixed
 	 */
-	function getPrimary($throw = TRUE);
+	function getPrimary(bool $throw = TRUE);
 
 	/**
 	 * Returns row signature (composition of primary keys)
-	 * @param  bool
-	 * @return string
 	 */
-	function getSignature($throw = TRUE);
+	function getSignature(bool $throw = TRUE): string;
 
 	/**
 	 * Returns referencing rows.
-	 * @param  string
-	 * @param  string
-	 * @return GroupedSelection
 	 */
-	function related($key, $throughColumn = NULL);
+	function related(string $key, string $throughColumn = NULL): GroupedSelection;
 
 	/**
 	 * Returns referenced row.
-	 * @param  string
-	 * @param  string
 	 * @return IRow|NULL if the row does not exist
 	 */
-	function ref($key, $throughColumn = NULL);
+	function ref(string $key, string $throughColumn = NULL): ?IRow;
 
 }
diff --git a/src/Database/Table/Selection.php b/src/Database/Table/Selection.php
index 98851d955..67255226f 100644
--- a/src/Database/Table/Selection.php
+++ b/src/Database/Table/Selection.php
@@ -82,12 +82,9 @@ class Selection implements \Iterator, IRowContainer, \ArrayAccess, \Countable
 
 	/**
 	 * Creates filtered table representation.
-	 * @param  Context
-	 * @param  IConventions
-	 * @param  string  table name
-	 * @param  Nette\Caching\IStorage|NULL
+	 * @param  string $tableName  table name
 	 */
-	public function __construct(Context $context, IConventions $conventions, $tableName, Nette\Caching\IStorage $cacheStorage = NULL)
+	public function __construct(Context $context, IConventions $conventions, string $tableName, Nette\Caching\IStorage $cacheStorage = NULL)
 	{
 		$this->context = $context;
 		$this->conventions = $conventions;
@@ -112,20 +109,16 @@ public function __clone()
 	}
 
 
-	/**
-	 * @return string
-	 */
-	public function getName()
+	public function getName(): string
 	{
 		return $this->name;
 	}
 
 
 	/**
-	 * @param  bool
 	 * @return string|array|NULL
 	 */
-	public function getPrimary($throw = TRUE)
+	public function getPrimary(bool $throw = TRUE)
 	{
 		if ($this->primary === NULL && $throw) {
 			throw new \LogicException("Table '{$this->name}' does not have a primary key.");
@@ -134,10 +127,7 @@ public function getPrimary($throw = TRUE)
 	}
 
 
-	/**
-	 * @return string|NULL
-	 */
-	public function getPrimarySequence()
+	public function getPrimarySequence(): ?string
 	{
 		if ($this->primarySequence === FALSE) {
 			$this->primarySequence = $this->context->getStructure()->getPrimaryKeySequence($this->name);
@@ -148,20 +138,16 @@ public function getPrimarySequence()
 
 
 	/**
-	 * @param  string
 	 * @return static
 	 */
-	public function setPrimarySequence($sequence)
+	public function setPrimarySequence(string $sequence)
 	{
 		$this->primarySequence = $sequence;
 		return $this;
 	}
 
 
-	/**
-	 * @return string
-	 */
-	public function getSql()
+	public function getSql(): string
 	{
 		return $this->sqlBuilder->buildSelectQuery($this->getPreviousAccessedColumns());
 	}
@@ -187,9 +173,8 @@ public function getPreviousAccessedColumns()
 
 	/**
 	 * @internal
-	 * @return SqlBuilder
 	 */
-	public function getSqlBuilder()
+	public function getSqlBuilder(): SqlBuilder
 	{
 		return $this->sqlBuilder;
 	}
@@ -203,7 +188,7 @@ public function getSqlBuilder()
 	 * @param  mixed primary key
 	 * @return IRow|NULL if there is no such row
 	 */
-	public function get($key)
+	public function get($key): ?IRow
 	{
 		$clone = clone $this;
 		return $clone->wherePrimary($key)->fetch();
@@ -213,7 +198,7 @@ public function get($key)
 	/**
 	 * @inheritDoc
 	 */
-	public function fetch()
+	public function fetch(): ?Nette\Database\IRow
 	{
 		$this->execute();
 		$return = current($this->data);
@@ -245,7 +230,7 @@ public function fetchField($column = NULL)
 	/**
 	 * @inheritDoc
 	 */
-	public function fetchPairs($key = NULL, $value = NULL)
+	public function fetchPairs($key = NULL, $value = NULL): array
 	{
 		return Nette\Database\Helpers::toPairs($this->fetchAll(), $key, $value);
 	}
@@ -254,7 +239,7 @@ public function fetchPairs($key = NULL, $value = NULL)
 	/**
 	 * @inheritDoc
 	 */
-	public function fetchAll()
+	public function fetchAll(): array
 	{
 		return iterator_to_array($this);
 	}
@@ -263,7 +248,7 @@ public function fetchAll()
 	/**
 	 * @inheritDoc
 	 */
-	public function fetchAssoc($path)
+	public function fetchAssoc(string $path): array
 	{
 		$rows = array_map('iterator_to_array', $this->fetchAll());
 		return Nette\Utils\Arrays::associate($rows, $path);
@@ -331,7 +316,7 @@ public function where($condition, ...$params)
 	 * @param  mixed
 	 * @return static
 	 */
-	public function joinWhere($tableChain, $condition, ...$params)
+	public function joinWhere(string $tableChain, string $condition, ...$params)
 	{
 		$this->condition($condition, $params, $tableChain);
 		return $this;
@@ -341,9 +326,8 @@ public function joinWhere($tableChain, $condition, ...$params)
 	/**
 	 * Adds condition, more calls appends with AND.
 	 * @param  string|string[] condition possibly containing ?
-	 * @return void
 	 */
-	protected function condition($condition, array $params, $tableChain = NULL)
+	protected function condition($condition, array $params, $tableChain = NULL): void
 	{
 		$this->emptyResultSet();
 		if (is_array($condition) && $params === []) { // where(array('column1' => 1, 'column2 > ?' => 2))
@@ -401,7 +385,7 @@ public function whereOr(array $parameters)
 	 * @param  string for example 'column1, column2 DESC'
 	 * @return static
 	 */
-	public function order($columns, ...$params)
+	public function order(string $columns, ...$params)
 	{
 		$this->emptyResultSet();
 		$this->sqlBuilder->addOrder($columns, ...$params);
@@ -411,11 +395,9 @@ public function order($columns, ...$params)
 
 	/**
 	 * Sets limit clause, more calls rewrite old values.
-	 * @param  int
-	 * @param  int
 	 * @return static
 	 */
-	public function limit($limit, $offset = NULL)
+	public function limit(int $limit, int $offset = NULL)
 	{
 		$this->emptyResultSet();
 		$this->sqlBuilder->setLimit($limit, $offset);
@@ -425,11 +407,9 @@ public function limit($limit, $offset = NULL)
 
 	/**
 	 * Sets offset using page number, more calls rewrite old values.
-	 * @param  int
-	 * @param  int
 	 * @return static
 	 */
-	public function page($page, $itemsPerPage, &$numOfPages = NULL)
+	public function page(int $page, int $itemsPerPage, &$numOfPages = NULL)
 	{
 		if (func_num_args() > 2) {
 			$numOfPages = (int) ceil($this->count('*') / $itemsPerPage);
@@ -443,10 +423,9 @@ public function page($page, $itemsPerPage, &$numOfPages = NULL)
 
 	/**
 	 * Sets group clause, more calls rewrite old value.
-	 * @param  string
 	 * @return static
 	 */
-	public function group($columns, ...$params)
+	public function group(string $columns, ...$params)
 	{
 		$this->emptyResultSet();
 		$this->sqlBuilder->setGroup($columns, ...$params);
@@ -456,10 +435,9 @@ public function group($columns, ...$params)
 
 	/**
 	 * Sets having clause, more calls rewrite old value.
-	 * @param  string
 	 * @return static
 	 */
-	public function having($having, ...$params)
+	public function having(string $having, ...$params)
 	{
 		$this->emptyResultSet();
 		$this->sqlBuilder->setHaving($having, ...$params);
@@ -469,11 +447,9 @@ public function having($having, ...$params)
 
 	/**
 	 * Aliases table. Example ':book:book_tag.tag', 'tg'
-	 * @param  string
-	 * @param  string
 	 * @return static
 	 */
-	public function alias($tableChain, $alias)
+	public function alias(string $tableChain, string $alias)
 	{
 		$this->sqlBuilder->addAlias($tableChain, $alias);
 		return $this;
@@ -486,9 +462,8 @@ public function alias($tableChain, $alias)
 	/**
 	 * Executes aggregation function.
 	 * @param  string select call in "FUNCTION(column)" format
-	 * @return int
 	 */
-	public function aggregation($function)
+	public function aggregation(string $function): int
 	{
 		$selection = $this->createSelectionInstance();
 		$selection->getSqlBuilder()->importConditions($this->getSqlBuilder());
@@ -502,9 +477,8 @@ public function aggregation($function)
 	/**
 	 * Counts number of rows.
 	 * @param  string  if it is not provided returns count of result rows, otherwise runs new sql counting query
-	 * @return int
 	 */
-	public function count($column = NULL)
+	public function count(string $column = NULL): int
 	{
 		if (!$column) {
 			$this->execute();
@@ -516,10 +490,8 @@ public function count($column = NULL)
 
 	/**
 	 * Returns minimum value from a column.
-	 * @param  string
-	 * @return int
 	 */
-	public function min($column)
+	public function min(string $column): int
 	{
 		return $this->aggregation("MIN($column)");
 	}
@@ -527,10 +499,8 @@ public function min($column)
 
 	/**
 	 * Returns maximum value from a column.
-	 * @param  string
-	 * @return int
 	 */
-	public function max($column)
+	public function max(string $column): int
 	{
 		return $this->aggregation("MAX($column)");
 	}
@@ -538,10 +508,8 @@ public function max($column)
 
 	/**
 	 * Returns sum of values in a column.
-	 * @param  string
-	 * @return int
 	 */
-	public function sum($column)
+	public function sum(string $column): int
 	{
 		return $this->aggregation("SUM($column)");
 	}
@@ -593,43 +561,31 @@ protected function execute()
 	}
 
 
-	/**
-	 * @return ActiveRow
-	 */
-	protected function createRow(array $row)
+	protected function createRow(array $row): ActiveRow
 	{
 		return new ActiveRow($row, $this);
 	}
 
 
-	/**
-	 * @return self
-	 */
-	public function createSelectionInstance($table = NULL)
+	public function createSelectionInstance($table = NULL): self
 	{
 		return new self($this->context, $this->conventions, $table ?: $this->name, $this->cache ? $this->cache->getStorage() : NULL);
 	}
 
 
-	/**
-	 * @return GroupedSelection
-	 */
-	protected function createGroupedSelectionInstance($table, $column)
+	protected function createGroupedSelectionInstance($table, $column): GroupedSelection
 	{
 		return new GroupedSelection($this->context, $this->conventions, $table, $column, $this, $this->cache ? $this->cache->getStorage() : NULL);
 	}
 
 
-	/**
-	 * @return Nette\Database\ResultSet
-	 */
-	protected function query($query)
+	protected function query($query): Nette\Database\ResultSet
 	{
 		return $this->context->queryArgs($query, $this->sqlBuilder->getParameters());
 	}
 
 
-	protected function emptyResultSet($clearCache = TRUE, $deleteRererencedCache = TRUE)
+	protected function emptyResultSet(bool $clearCache = TRUE, bool $deleteRererencedCache = TRUE): void
 	{
 		if ($this->rows !== NULL && $clearCache) {
 			$this->saveCacheState();
@@ -650,7 +606,7 @@ protected function emptyResultSet($clearCache = TRUE, $deleteRererencedCache = T
 	}
 
 
-	protected function saveCacheState()
+	protected function saveCacheState(): void
 	{
 		if ($this->observeCache === $this && $this->cache && !$this->sqlBuilder->getSelect() && $this->accessedColumns !== $this->previousAccessedColumns) {
 			$previousAccessed = $this->cache->load($this->getGeneralCacheKey());
@@ -681,7 +637,7 @@ protected function getRefTable(&$refPath)
 	/**
 	 * Loads refCache references
 	 */
-	protected function loadRefCache()
+	protected function loadRefCache(): void
 	{
 	}
 
@@ -689,9 +645,8 @@ protected function loadRefCache()
 	/**
 	 * Returns general cache key independent on query parameters or sql limit
 	 * Used e.g. for previously accessed columns caching
-	 * @return string
 	 */
-	protected function getGeneralCacheKey()
+	protected function getGeneralCacheKey(): string
 	{
 		if ($this->generalCacheKey) {
 			return $this->generalCacheKey;
@@ -711,9 +666,8 @@ protected function getGeneralCacheKey()
 	/**
 	 * Returns object specific cache key dependent on query parameters
 	 * Used e.g. for reference memory caching
-	 * @return string
 	 */
-	protected function getSpecificCacheKey()
+	protected function getSpecificCacheKey(): string
 	{
 		if ($this->specificCacheKey) {
 			return $this->specificCacheKey;
@@ -726,10 +680,9 @@ protected function getSpecificCacheKey()
 	/**
 	 * @internal
 	 * @param  string|NULL column name or NULL to reload all columns
-	 * @param  bool
 	 * @return bool if selection requeried for more columns.
 	 */
-	public function accessColumn($key, $selectColumn = TRUE)
+	public function accessColumn(?string $key, bool $selectColumn = TRUE): bool
 	{
 		if (!$this->cache) {
 			return FALSE;
@@ -783,9 +736,8 @@ public function accessColumn($key, $selectColumn = TRUE)
 
 	/**
 	 * @internal
-	 * @param  string
 	 */
-	public function removeAccessColumn($key)
+	public function removeAccessColumn(string $key): void
 	{
 		if ($this->cache && is_array($this->accessedColumns)) {
 			$this->accessedColumns[$key] = FALSE;
@@ -795,9 +747,8 @@ public function removeAccessColumn($key)
 
 	/**
 	 * Returns if selection requeried for more columns.
-	 * @return bool
 	 */
-	public function getDataRefreshed()
+	public function getDataRefreshed(): bool
 	{
 		return $this->dataRefreshed;
 	}
@@ -877,10 +828,9 @@ public function insert($data)
 	/**
 	 * Updates all rows in result set.
 	 * Joins in UPDATE are supported only in MySQL
-	 * @param  iterable ($column => $value)
 	 * @return int number of affected rows
 	 */
-	public function update($data)
+	public function update(iterable $data): int
 	{
 		if ($data instanceof \Traversable) {
 			$data = iterator_to_array($data);
@@ -904,7 +854,7 @@ public function update($data)
 	 * Deletes all rows in result set.
 	 * @return int number of affected rows
 	 */
-	public function delete()
+	public function delete(): int
 	{
 		return $this->query($this->sqlBuilder->buildDeleteQuery())->getRowCount();
 	}
@@ -915,12 +865,9 @@ public function delete()
 
 	/**
 	 * Returns referenced row.
-	 * @param  ActiveRow
-	 * @param  string|NULL
-	 * @param  string|NULL
 	 * @return ActiveRow|NULL|FALSE NULL if the row does not exist, FALSE if the relationship does not exist
 	 */
-	public function getReferencedTable(ActiveRow $row, $table, $column = NULL)
+	public function getReferencedTable(ActiveRow $row, ?string $table, string $column = NULL)
 	{
 		if (!$column) {
 			$belongsTo = $this->conventions->getBelongsToReference($this->name, $table);
@@ -964,12 +911,9 @@ public function getReferencedTable(ActiveRow $row, $table, $column = NULL)
 
 	/**
 	 * Returns referencing rows.
-	 * @param  string
-	 * @param  string
-	 * @param  int primary key
-	 * @return GroupedSelection|NULL
+	 * @param  int $active primary key
 	 */
-	public function getReferencingTable($table, $column, $active = NULL)
+	public function getReferencingTable(string $table, string $column = NULL, int $active = NULL): ?GroupedSelection
 	{
 		if (strpos($table, '.') !== FALSE) {
 			[$table, $column] = explode('.', $table);
@@ -996,7 +940,7 @@ public function getReferencingTable($table, $column, $active = NULL)
 	/********************* interface Iterator ****************d*g**/
 
 
-	public function rewind()
+	public function rewind(): void
 	{
 		$this->execute();
 		$this->keys = array_keys($this->data);
@@ -1024,7 +968,7 @@ public function key()
 	}
 
 
-	public function next()
+	public function next(): void
 	{
 		do {
 			next($this->keys);
@@ -1032,7 +976,7 @@ public function next()
 	}
 
 
-	public function valid()
+	public function valid(): bool
 	{
 		return current($this->keys) !== FALSE;
 	}
@@ -1045,9 +989,8 @@ public function valid()
 	 * Mimic row.
 	 * @param  string row ID
 	 * @param  IRow
-	 * @return void
 	 */
-	public function offsetSet($key, $value)
+	public function offsetSet($key, $value): void
 	{
 		$this->execute();
 		$this->rows[$key] = $value;
@@ -1059,7 +1002,7 @@ public function offsetSet($key, $value)
 	 * @param  string row ID
 	 * @return IRow|NULL if there is no such row
 	 */
-	public function offsetGet($key)
+	public function offsetGet($key): ?IRow
 	{
 		$this->execute();
 		return $this->rows[$key];
@@ -1069,9 +1012,8 @@ public function offsetGet($key)
 	/**
 	 * Tests if row exists.
 	 * @param  string row ID
-	 * @return bool
 	 */
-	public function offsetExists($key)
+	public function offsetExists($key): bool
 	{
 		$this->execute();
 		return isset($this->rows[$key]);
@@ -1081,9 +1023,8 @@ public function offsetExists($key)
 	/**
 	 * Removes row from result set.
 	 * @param  string row ID
-	 * @return void
 	 */
-	public function offsetUnset($key)
+	public function offsetUnset($key): void
 	{
 		$this->execute();
 		unset($this->rows[$key], $this->data[$key]);
diff --git a/src/Database/Table/SqlBuilder.php b/src/Database/Table/SqlBuilder.php
index 8376d0292..a09bf0652 100644
--- a/src/Database/Table/SqlBuilder.php
+++ b/src/Database/Table/SqlBuilder.php
@@ -93,7 +93,7 @@ class SqlBuilder
 	private $expandingJoins = [];
 
 
-	public function __construct($tableName, Context $context)
+	public function __construct(string $tableName, Context $context)
 	{
 		$this->tableName = $tableName;
 		$this->driver = $context->getConnection()->getSupplementalDriver();
@@ -105,28 +105,19 @@ public function __construct($tableName, Context $context)
 	}
 
 
-	/**
-	 * @return string
-	 */
-	public function getTableName()
+	public function getTableName(): string
 	{
 		return $this->tableName;
 	}
 
 
-	/**
-	 * @param  string
-	 */
-	public function buildInsertQuery()
+	public function buildInsertQuery(): string
 	{
 		return "INSERT INTO {$this->delimitedTable}";
 	}
 
 
-	/**
-	 * @param  string
-	 */
-	public function buildUpdateQuery()
+	public function buildUpdateQuery(): string
 	{
 		$query = "UPDATE {$this->delimitedTable} SET ?set" . $this->tryDelimite($this->buildConditions());
 		if ($this->limit !== NULL || $this->offset) {
@@ -137,10 +128,7 @@ public function buildUpdateQuery()
 	}
 
 
-	/**
-	 * @param  string
-	 */
-	public function buildDeleteQuery()
+	public function buildDeleteQuery(): string
 	{
 		$query = "DELETE FROM {$this->delimitedTable}" . $this->tryDelimite($this->buildConditions());
 		if ($this->limit !== NULL || $this->offset) {
@@ -153,9 +141,8 @@ public function buildDeleteQuery()
 
 	/**
 	 * Returns select query hash for caching.
-	 * @return string
 	 */
-	public function getSelectQueryHash(array $columns = NULL)
+	public function getSelectQueryHash(array $columns = NULL): string
 	{
 		$parts = [
 			'delimitedTable' => $this->delimitedTable,
@@ -187,9 +174,8 @@ public function getSelectQueryHash(array $columns = NULL)
 	/**
 	 * Returns SQL query.
 	 * @param  string[] list of columns
-	 * @return string
 	 */
-	public function buildSelectQuery(array $columns = NULL)
+	public function buildSelectQuery(array $columns = NULL): string
 	{
 		if (!$this->order && ($this->limit !== NULL || $this->offset)) {
 			$this->order = array_map(
@@ -237,10 +223,7 @@ function ($col) { return "$this->tableName.$col"; },
 	}
 
 
-	/**
-	 * @return array
-	 */
-	public function getParameters()
+	public function getParameters(): array
 	{
 		if (!isset($this->parameters['joinConditionSorted'])) {
 			$this->buildSelectQuery();
@@ -256,7 +239,7 @@ public function getParameters()
 	}
 
 
-	public function importConditions(SqlBuilder $builder)
+	public function importConditions(SqlBuilder $builder): void
 	{
 		$this->where = $builder->where;
 		$this->joinCondition = $builder->joinCondition;
@@ -271,7 +254,7 @@ public function importConditions(SqlBuilder $builder)
 	/********************* SQL selectors ****************d*g**/
 
 
-	public function addSelect($columns, ...$params)
+	public function addSelect($columns, ...$params): void
 	{
 		if (is_array($columns)) {
 			throw new Nette\InvalidArgumentException('Select column must be a string.');
@@ -281,28 +264,19 @@ public function addSelect($columns, ...$params)
 	}
 
 
-	/**
-	 * @return array
-	 */
-	public function getSelect()
+	public function getSelect(): array
 	{
 		return $this->select;
 	}
 
 
-	/**
-	 * @return bool
-	 */
-	public function addWhere($condition, ...$params)
+	public function addWhere($condition, ...$params): bool
 	{
 		return $this->addCondition($condition, $params, $this->where, $this->parameters['where']);
 	}
 
 
-	/**
-	 * @return array
-	 */
-	public function addJoinCondition($tableChain, $condition, ...$params)
+	public function addJoinCondition($tableChain, $condition, ...$params): bool
 	{
 		$this->parameters['joinConditionSorted'] = NULL;
 		if (!isset($this->joinCondition[$tableChain])) {
@@ -312,10 +286,7 @@ public function addJoinCondition($tableChain, $condition, ...$params)
 	}
 
 
-	/**
-	 * @return bool
-	 */
-	protected function addCondition($condition, array $params, array &$conditions, array &$conditionsParameters)
+	protected function addCondition($condition, array $params, array &$conditions, array &$conditionsParameters): bool
 	{
 		if (is_array($condition) && !empty($params[0]) && is_array($params[0])) {
 			return $this->addConditionComposition($condition, $params[0], $conditions, $conditionsParameters);
@@ -431,10 +402,7 @@ protected function addCondition($condition, array $params, array &$conditions, a
 	}
 
 
-	/**
-	 * @return array
-	 */
-	public function getConditions()
+	public function getConditions(): array
 	{
 		return array_values($this->conditions);
 	}
@@ -442,11 +410,8 @@ public function getConditions()
 
 	/**
 	 * Adds alias.
-	 * @param  string
-	 * @param  string
-	 * @return void
 	 */
-	public function addAlias($chain, $alias)
+	public function addAlias(string $chain, string $alias): void
 	{
 		if (isset($chain[0]) && $chain[0] !== '.' && $chain[0] !== ':') {
 			$chain = '.' . $chain; // unified chain format
@@ -456,12 +421,7 @@ public function addAlias($chain, $alias)
 	}
 
 
-	/**
-	 * @param  string
-	 * @param  string
-	 * @return void
-	 */
-	protected function checkUniqueTableName($tableName, $chain)
+	protected function checkUniqueTableName(string $tableName, string $chain): void
 	{
 		if (isset($this->aliases[$tableName]) && ('.' . $tableName === $chain)) {
 			$chain = $this->aliases[$tableName];
@@ -476,86 +436,66 @@ protected function checkUniqueTableName($tableName, $chain)
 	}
 
 
-	public function addOrder($columns, ...$params)
+	public function addOrder($columns, ...$params): void
 	{
 		$this->order[] = $columns;
 		$this->parameters['order'] = array_merge($this->parameters['order'], $params);
 	}
 
 
-	public function setOrder(array $columns, array $parameters)
+	public function setOrder(array $columns, array $parameters): void
 	{
 		$this->order = $columns;
 		$this->parameters['order'] = $parameters;
 	}
 
 
-	/**
-	 * @return array
-	 */
-	public function getOrder()
+	public function getOrder(): array
 	{
 		return $this->order;
 	}
 
 
-	/**
-	 * @param  int|NULL
-	 * @param  int|NULL
-	 * @return void
-	 */
-	public function setLimit($limit, $offset)
+	public function setLimit(?int $limit, ?int $offset): void
 	{
 		$this->limit = $limit;
 		$this->offset = $offset;
 	}
 
 
-	/**
-	 * @return int|NULL
-	 */
-	public function getLimit()
+	public function getLimit(): ?int
 	{
 		return $this->limit;
 	}
 
 
-	/**
-	 * @return int|NULL
-	 */
-	public function getOffset()
+	public function getOffset(): ?int
 	{
 		return $this->offset;
 	}
 
 
-	public function setGroup($columns, ...$params)
+	public function setGroup($columns, ...$params): void
 	{
 		$this->group = $columns;
 		$this->parameters['group'] = $params;
 	}
 
 
-	/**
-	 * @return string
-	 */
-	public function getGroup()
+	public function getGroup(): string
 	{
 		return $this->group;
 	}
 
 
-	public function setHaving($having, ...$params)
+	public function setHaving($having, ...$params): void
 	{
 		$this->having = $having;
 		$this->parameters['having'] = $params;
 	}
 
 
-	/**
-	 * @return string
-	 */
-	public function getHaving()
+	public function getHaving(): string
 	{
 		return $this->having;
 	}
@@ -564,19 +504,13 @@ public function getHaving()
 	/********************* SQL building ****************d*g**/
 
 
-	/**
-	 * @return string
-	 */
-	protected function buildSelect(array $columns)
+	protected function buildSelect(array $columns): string
 	{
 		return 'SELECT ' . implode(', ', $columns);
 	}
 
 
-	/**
-	 * @return array
-	 */
-	protected function parseJoinConditions(&$joins, $joinConditions)
+	protected function parseJoinConditions(&$joins, $joinConditions): array
 	{
 		$tableJoins = $leftJoinDependency = $finalJoinConditions = [];
 		foreach ($joinConditions as $tableChain => &$joinCondition) {
@@ -609,7 +543,7 @@ protected function parseJoinConditions(&$joins, $joinConditions)
 	}
 
 
-	protected function getSortedJoins($table, &$leftJoinDependency, &$tableJoins, &$finalJoins)
+	protected function getSortedJoins(string $table, &$leftJoinDependency, &$tableJoins, &$finalJoins): void
 	{
 		if (isset($this->expandingJoins[$table])) {
 			$path = implode("' => '", array_map(function($value) { return $this->reservedTableNames[$value]; }, array_merge(array_keys($this->expandingJoins), [$table])));
@@ -644,7 +578,7 @@ protected function getSortedJoins($table, &$leftJoinDependency, &$tableJoins, &$
 	}
 
 
-	protected function parseJoins(&$joins, &$query)
+	protected function parseJoins(&$joins, &$query): void
 	{
 		$query = preg_replace_callback($this->getColumnChainsRegxp(), function ($match) use (&$joins) {
 			return $this->parseJoinsCb($joins, $match);
@@ -652,10 +586,7 @@ protected function parseJoins(&$joins, &$query)
 	}
 
 
-	/**
-	 * @return string
-	 */
-	private function getColumnChainsRegxp()
+	private function getColumnChainsRegxp(): string
 	{
 		return '~
 			(?(DEFINE)
@@ -668,10 +599,7 @@ private function getColumnChainsRegxp()
 	}
 
 
-	/**
-	 * @return string
-	 */
-	public function parseJoinsCb(&$joins, $match)
+	public function parseJoinsCb(&$joins, $match): string
 	{
 		$chain = $match['chain'];
 		if (!empty($chain[0]) && ($chain[0] !== '.' && $chain[0] !== ':')) {
@@ -777,10 +705,7 @@ public function parseJoinsCb(&$joins, $match)
 	}
 
 
-	/**
-	 * @return string
-	 */
-	protected function buildQueryJoins(array $joins, array $leftJoinConditions = [])
+	protected function buildQueryJoins(array $joins, array $leftJoinConditions = []): string
 	{
 		$return = '';
 		foreach ($joins as [$joinTable, $joinAlias, $table, $tableColumn, $joinColumn]) {
@@ -793,10 +718,7 @@ protected function buildQueryJoins(array $joins, array $leftJoinConditions = [])
 	}
 
 
-	/**
-	 * @return array
-	 */
-	protected function buildJoinConditions()
+	protected function buildJoinConditions(): array
 	{
 		$conditions = [];
 		foreach ($this->joinCondition as $tableChain => $joinConditions) {
@@ -806,19 +728,13 @@ protected function buildJoinConditions()
 	}
 
 
-	/**
-	 * @return string
-	 */
-	protected function buildConditions()
+	protected function buildConditions(): string
 	{
 		return $this->where ? ' WHERE (' . implode(') AND (', $this->where) . ')' : '';
 	}
 
 
-	/**
-	 * @return string
-	 */
-	protected function buildQueryEnd()
+	protected function buildQueryEnd(): string
 	{
 		$return = '';
 		if ($this->group) {
@@ -834,10 +750,7 @@ protected function buildQueryEnd()
 	}
 
 
-	/**
-	 * @return string
-	 */
-	protected function tryDelimite($s)
+	protected function tryDelimite(string $s): string
 	{
 		return preg_replace_callback('#(?<=[^\w`"\[?]|^)[a-z_][a-z0-9_]*(?=[^\w`"(\]]|\z)#i', function ($m) {
 			return strtoupper($m[0]) === $m[0] ? $m[0] : $this->driver->delimite($m[0]);
@@ -845,10 +758,7 @@ protected function tryDelimite($s)
 	}
 
 
-	/**
-	 * @return bool
-	 */
-	protected function addConditionComposition(array $columns, array $parameters, array &$conditions, array &$conditionsParameters)
+	protected function addConditionComposition(array $columns, array $parameters, array &$conditions, array &$conditionsParameters): bool
 	{
 		if ($this->driver->isSupported(ISupplementalDriver::SUPPORT_MULTI_COLUMN_AS_OR_COND)) {
 			$conditionFragment = '(' . implode(' = ? AND ', $columns) . ' = ?) OR ';
@@ -860,10 +770,7 @@ protected function addConditionComposition(array $columns, array $parameters, ar
 	}
 
 
-	/**
-	 * @return string
-	 */
-	private function getConditionHash($condition, array $parameters)
+	private function getConditionHash($condition, array $parameters): string
 	{
 		foreach ($parameters as $key => &$parameter) {
 			if ($parameter instanceof Selection) {
@@ -880,10 +787,7 @@ private function getConditionHash($condition, array $parameters)
 	}
 
 
-	/**
-	 * @return array
-	 */
-	private function getCachedTableList()
+	private function getCachedTableList(): array
 	{
 		if (!$this->cacheTableList) {
 			$this->cacheTableList = array_flip(array_map(function ($pair) {
diff --git a/tests/Database/Table/Selection.page().phpt b/tests/Database/Table/Selection.page().phpt
index dcdf78126..998f9f793 100644
--- a/tests/Database/Table/Selection.page().phpt
+++ b/tests/Database/Table/Selection.page().phpt
@@ -59,11 +59,3 @@ test(function () use ($context) { //less items than $itemsPerPage
 	$tags = $context->table('tag')->page(1, 100);
 	Assert::equal(4, count($tags)); //all four items from db
 });
-
-// SQL Server throw PDOException 'The number of rows provided for a FETCH clause must be greater then zero.'
-if ($driverName !== 'sqlsrv') {
-	Assert::error(function () use ($context) { //invalid params
-		$tags = $context->table('tag')->page('foo', 'bar');
-		Assert::equal(0, count($tags)); //no items
-	}, PHP_VERSION_ID >= 70100 ? [[E_WARNING, 'A non-numeric value encountered']] : []);
-}
diff --git a/tests/Database/Table/SqlBuilder.addAlias().phpt b/tests/Database/Table/SqlBuilder.addAlias().phpt
index 7643e4d55..10af83f67 100644
--- a/tests/Database/Table/SqlBuilder.addAlias().phpt
+++ b/tests/Database/Table/SqlBuilder.addAlias().phpt
@@ -17,11 +17,11 @@ Nette\Database\Helpers::loadFromFile($connection, __DIR__ . "/../files/{$driverN
 
 class SqlBuilderMock extends SqlBuilder
 {
-	public function parseJoins(&$joins, &$query, $inner = FALSE)
+	public function parseJoins(&$joins, &$query, $inner = FALSE): void
 	{
 		parent::parseJoins($joins, $query);
 	}
-	public function buildQueryJoins(array $joins, array $leftJoinConditions = [])
+	public function buildQueryJoins(array $joins, array $leftJoinConditions = []): string
 	{
 		return parent::buildQueryJoins($joins, $leftJoinConditions);
 	}
diff --git a/tests/Database/Table/SqlBuilder.parseJoinConditions().phpt b/tests/Database/Table/SqlBuilder.parseJoinConditions().phpt
index 84b659be7..7baa0a61c 100644
--- a/tests/Database/Table/SqlBuilder.parseJoinConditions().phpt
+++ b/tests/Database/Table/SqlBuilder.parseJoinConditions().phpt
@@ -17,19 +17,19 @@ Nette\Database\Helpers::loadFromFile($connection, __DIR__ . "/../files/{$driverN
 
 class SqlBuilderMock extends SqlBuilder
 {
-	public function parseJoinConditions(&$joins, $joinConditions)
+	public function parseJoinConditions(&$joins, $joinConditions): array
 	{
 		return parent::parseJoinConditions($joins, $joinConditions);
 	}
-	public function buildJoinConditions()
+	public function buildJoinConditions(): array
 	{
 		return parent::buildJoinConditions();
 	}
-	public function parseJoins(&$joins, &$query)
+	public function parseJoins(&$joins, &$query): void
 	{
 		parent::parseJoins($joins, $query);
 	}
-	public function buildQueryJoins(array $joins, array $leftJoinConditions = [])
+	public function buildQueryJoins(array $joins, array $leftJoinConditions = []): string
 	{
 		return parent::buildQueryJoins($joins, $leftJoinConditions);
 	}
diff --git a/tests/Database/Table/SqlBuilder.parseJoins().phpt b/tests/Database/Table/SqlBuilder.parseJoins().phpt
index 7b7a4f647..4184e1ecb 100644
--- a/tests/Database/Table/SqlBuilder.parseJoins().phpt
+++ b/tests/Database/Table/SqlBuilder.parseJoins().phpt
@@ -19,11 +19,11 @@ Nette\Database\Helpers::loadFromFile($connection, __DIR__ . "/../files/{$driverN
 
 class SqlBuilderMock extends SqlBuilder
 {
-	public function parseJoins(&$joins, &$query, $inner = FALSE)
+	public function parseJoins(&$joins, &$query, $inner = FALSE): void
 	{
 		parent::parseJoins($joins, $query);
 	}
-	public function buildQueryJoins(array $joins, array $leftJoinConditions = [])
+	public function buildQueryJoins(array $joins, array $leftJoinConditions = []): string
 	{
 		return parent::buildQueryJoins($joins, $leftJoinConditions);
 	}
diff --git a/tests/Database/Table/bugs/Selection.emptyResultSet.phpt b/tests/Database/Table/bugs/Selection.emptyResultSet.phpt
index d2ae97128..ca30b6d8f 100644
--- a/tests/Database/Table/bugs/Selection.emptyResultSet.phpt
+++ b/tests/Database/Table/bugs/Selection.emptyResultSet.phpt
@@ -20,7 +20,7 @@ test(function () use ($context) {
 	$context->table('book')->get(2)->author->update(['name' => 'New name']);
 	$context->table('book')->get(2)->update(['title' => 'New book title']);
 
-	$selection->limit(NULL); //should invalidate cache of data and references
+	$selection->limit(1); //should invalidate cache of data and references
 	$book = $selection->get(2);
 
 	Assert::same('New book title', $book->title); //data cache invalidated