MySqlExpress get rows from MySQL table and convert it into Class Objects in C#. For saving data, Class Objects and be passed for executing INSERT or UPDATE. It can also performs INSERT/UPDATE by using Dictionary. It simplifies the usage of MySQL in C#.
This class library aims to encourage rapid application development with MySQL.
Github: https://github.com/adriancs2/MySqlExpress
Nuget for MySqlConnector (MIT) - https://www.nuget.org/packages/MySqlExpress
PM> NuGet\Install-Package MySqlExpress
Nuget for MySql.Data (Oracle) - https://www.nuget.org/packages/MySqlExpress.MySql.Data
PM> NuGet\Install-Package MySqlExpress.MySql.Data
Download MySqlExpress Helper: https://github.com/adriancs2/MySqlExpress/releases
The Demo of MySqlExpress (Available in source code):
MySqlExpress consists of 2 parts.
The first part is the C# class library of MySqlExpress. It introduces some "shortcuts" as to simplify the execution of tasks related to MySQL.
To begin with, download the source code and add the class file "MySqlExpress.cs" into your project,
or add the referrence of the project of MySqlExpress into your project,
or install the Nuget package of MySqlExpress into your project.
The second part is a software called "MySqlExpress Helper.exe". The main function of this software is to generate C# class objects, which will be explained in details below. I'll refer this small program as the "Helper App" for the rest of this article.
Download MySqlExpress Helper: https://github.com/adriancs2/MySqlExpress/releases
MySqlExpress is built on top of MySqlConnector (MIT) library. If you wish to use another connector or provider, you can download the source code and compile it with your favorite connector.
As usual, to begin coding with MySQL, first add the following using statement to allow the usage of MySqlconnector (MIT) library.
using MySqlConnector;In this article, let's assume that we store the MySQL connection string as a static field. For example:
public class config
{
public static string ConnString =
"server=localhost;user=root;pwd=1234;database=test;";
}Hence, we can obtain the connection string anywhere in the project as below:
config.ConnStringHere is the standard MySQL connection code block:
using (MySqlConnection conn = new MySqlConnection(config.ConnString))
{
using (MySqlCommand cmd = new MySqlCommand())
{
cmd.Connection = conn;
conn.Open();
// execute queries
conn.Close();
}
}Declare a new MySqlExpress object to start using:
using (MySqlConnection conn = new MySqlConnection(config.ConnString))
{
using (MySqlCommand cmd = new MySqlCommand())
{
cmd.Connection = conn;
conn.Open();
MySqlExpress m = new MySqlExpress(cmd);
// perform queries
conn.Close();
}
}The standard MySQL connection code block shown above can be saved into Visual Studio toolbox bar. So, next time, whenever you need this code block, you can drag and drop from the toolbox bar.
Now the code block is saved at the toolbox.
Next time, whenever you need the code block, just drag it from the toolbox into the text editor.
- Start Transaction, Commit, Rollback
- Getting Rows of Objects from MySQL Table
- Getting a Customized Object Structure
- Getting a single value (ExecuteScalar)
- Save (v.17) - Saving Objects
- Insert Row (Save Data)
- Update Row (Update Data)
- Insert Update
- Generate Like String
- Execute a SQL statement
using (MySqlConnection conn = new MySqlConnection(config.ConnString))
{
using (MySqlCommand cmd = new MySqlCommand())
{
cmd.Connection = conn;
conn.Open();
MySqlExpress m = new MySqlExpress(cmd);
try
{
m.StartTransaction();
// perform lots of queries
// action success
m.Commit();
}
catch
{
// Error occur
m.Rollback();
}
conn.Close();
}
}There are a few benefits of using TRANSACTION in MySQL.
On a 7200 rpm HDD hard drive, the maximum I/O writes (numbers of SQL queries) that MySQL can executes is around 100 to 120 times.
Read more about MySQL Disk I/O Capacity at: https://dev.mysql.com/doc/refman/5.7/en/innodb-configuring-io-capacity.html
If you perform 1000 queries, they will be executed one by one, which will take around 4~7 seconds on HDD hard drive to complete.
By using TRANSACTION + COMMIT, all 1000 queries will all be executed at once. This saves a lots of disk operation time.
Sometimes, there are chains of operations which involves multiple tables and rows. Without transaction, if there is any bad thing or error occurs in the middle of the process, the whole operation will be terminated half way, resulting partial or incomplete data saving. Which would be a problematic to fix the data. Hence, TRANSACTION can prevent such thing happens. With transaction, the whole chain of operation will be cancelled.
ROLLBACK, means cancel. Discard all queries that sent during the TRANSACTION period.
Read more about transaction at here
Assume that, we have a MySQL table like this:
CREATE TABLE `player` (
`id` int unsigned NOT NULL AUTO_INCREMENT,
`code` varchar(10),
`name` varchar(300),
`date_register` datetime,
`tel` varchar(100),
`email` varchar(100),
`status` int unsigned,
PRIMARY KEY (`id`));First, creates a new class.
public class obPlayer
{
}The name of class. If the MySQL table's name is "player", you can name the class as "obPlayer".
"ob" means "object".
"obPlayer", an object of "Player".
But, anyway, you can name the class anything according to your personal flavor, of course.
Next, create the class object's fields or properties:
There are 3 modes of creating the fields or properties:
- Private Fields + Public Properties
- Public Properties
- Public Fields
Run the Helper app.
First Mode: Private Fields + Public Properties
Paste the text into the class:
public class obPlayer
{
int id = 0;
string code = "";
string name = "";
DateTime date_register = DateTime.MinValue;
string tel = "";
string email = "";
int status = 0;
public int Id { get { return id; } set { id = value; } }
public string Code { get { return code; } set { code = value; } }
public string Name { get { return name; } set { name = value; } }
public DateTime DateRegister { get { return date_register; } set { date_register = value; } }
public string Tel { get { return tel; } set { tel = value; } }
public string Email { get { return email; } set { email = value; } }
public int Status { get { return status; } set { status = value; } }
}The purpose using this combination (private fields + public properties):
Private fields are used to match the columns' name of MySQL table and map the data.
Public properties are used to convert the naming of the fields into C# Coding Naming Convertions, which is PascalCase:
Read more about C# Coding Naming Conventions
The MySQL column's naming conventions uses lower case and underscore to separate words.
Read more about MySQL Naming Conventions
The symbol of "_" (underscore) is considered less typing friendly than using just latin characters.
Therefore, converting the field name to PacalCase will align with the C# naming conventions and also increase the convenient and speed of coding.
Second Mode: Public Properties
Then, paste all the copied text into the class:
public class obPlayer
{
public int id { get; set; }
public string code { get; set; }
public string name { get; set; }
public DateTime date_register { get; set; }
public string tel { get; set; }
public string email { get; set; }
public int status { get; set; }
}Third Mode: Public Fields
public class obPlayer
{
public int id = 0;
public string code = "";
public string name = "";
public DateTime date_register = DateTime.MinValue;
public string tel = "";
public string email = "";
public int status = 0;
}Getting a single row of "Player" object
Here's the code of getting a single row of "Player" object.
int id = 1;
// declare the object
obPlayer p = null;
using (MySqlConnection conn = new MySqlConnection(config.ConnString))
{
using (MySqlCommand cmd = new MySqlCommand())
{
cmd.Connection = conn;
conn.Open();
MySqlExpress m = new MySqlExpress(cmd);
// parameterize the values
Dictionary<string, object> dicParam = new Dictionary<string, object>();
dicParam["@vid"] = id;
p = m.GetObject<obPlayer>($"select * from player where id=@vid;", dicParam);
conn.Close();
}
}Getting a list of objects (get multiple rows from a MySQL table):
// declare the object list
List<obPlayer> lst = null;
using (MySqlConnection conn = new MySqlConnection(config.ConnString))
{
using (MySqlCommand cmd = new MySqlCommand())
{
cmd.Connection = conn;
conn.Open();
MySqlExpress m = new MySqlExpress(cmd);
// parameterize the values
Dictionary<string, object> dicParam = new Dictionary<string, object>();
dicParam["@vname"] = "%adam%";
lst = m.GetObjectList<obPlayer>($"select * from player where name like @vname;", dicParam);
conn.Close();
}
}One of the typical example is multiple SQL JOIN statement. For example:
select a.*, b.`year`, c.name 'teamname', c.code 'teamcode', c.id 'teamid'
from player a
inner join player_team b on a.id=b.player_id
inner join team c on b.team_id=c.id;The output table structure is customized.
To create a non-standardized table's object structure, open the Helper program. Key in the customized SQL JOIN statement.
Create the custom class object:
public class obPlayerTeam
{
}Then, paste the copied text into the new custom object:
public class obPlayerTeam
{
int id = 0;
string code = "";
string name = "";
DateTime date_register = DateTime.MinValue;
string tel = "";
string email = "";
int status = 0;
int year = 0;
string teamname = "";
string teamcode = "";
int teamid = 0;
public int Id { get { return id; } set { id = value; } }
public string Code { get { return code; } set { code = value; } }
public string Name { get { return name; } set { name = value; } }
public DateTime DateRegister { get { return date_register; } set { date_register = value; } }
public string Tel { get { return tel; } set { tel = value; } }
public string Email { get { return email; } set { email = value; } }
public int Status { get { return status; } set { status = value; } }
public int Year { get { return year; } set { year = value; } }
public string Teamname { get { return teamname; } set { teamname = value; } }
public string Teamcode { get { return teamcode; } set { teamcode = value; } }
public int Teamid { get { return teamid; } set { teamid = value; } }
}Getting the customized table object:
// declare the object
List<obPlayerTeam> lst = null;
// parameterized the value
Dictionary<string, object> dicParam = new Dictionary<string, object>();
dicParam["@vname"] = "%adam%";
using (MySqlConnection conn = new MySqlConnection(config.ConnString))
{
using (MySqlCommand cmd = new MySqlCommand())
{
cmd.Connection = conn;
conn.Open();
MySqlExpress m = new MySqlExpress(cmd);
lst = m.GetObjectList<obPlayerTeam>(@"
select a.*, b.`year`, c.name 'teamname', c.code 'teamcode', c.id 'teamid'
from player a inner join player_team b on a.id=b.player_id
inner join team c on b.team_id=c.id
where a.name like @vname;", dicParam);
conn.Close();
}
}// int
int count = m.ExecuteScalar<int>("select count(*) from player;");
// datetime
DateTime d = m.ExecuteScalar<DateTime>("select date_register from player where id=2;");
// string
string name = m.ExecuteScalar<string>("select name from player where id=1;");Getting single value with parameters
// parameters
Dictionary<string, object> dicParam1 = new Dictionary<string, object>();
dicParam1["@vname"] = "%adam%";
Dictionary<string, object> dicParam2 = new Dictionary<string, object>();
dicParam2["@vid"] = 1;
// int
int count = m.ExecuteScalar<int>("select count(*) from player where name like @vname;", dicParam1);
// datetime
DateTime d = m.ExecuteScalar<DateTime>("select date_register from player where id=@vid;", dicParam2);
// string
string name = m.ExecuteScalar<string>("select name from player where id=@vid;", dicParam2);A combination of "INSERT" and "UPDATE". This method will first attempt to perform an INSERT. If the primary key of the data has already existed in MySQL table, then it will perform an UPDATE.
// Syntax
m.Save(tablename, class);
m.SaveList(tablename, List<class>);
// Example:
// Saving single object
m.Save("player", player);
// Saving list of objects
m.SaveList("player", lstPlayer);Performs INSERT by using dictionary.
Note: The dictionary values will be inserted as parameterized values
The field "id" is a primary key, auto-increment field. Therefore, we don't need to insert data for this field.
Delete the following line from the block:
dic["id"] =Fill in data into the dictionary:
Dictionary<string, object> dic = new Dictionary<string, object>();
dic["code"] = "AA001";
dic["name"] = "John Smith";
dic["date_register"] = DateTime.Now;
dic["tel"] = "1298343223";
dic["email"] = "[email protected]";
dic["status"] = 1;
m.Insert("player", dic);Run the following code to obtain new inserted ID:
m.LastInsertIdObtain the LAST INSERT ID:
Dictionary<string, object> dic = new Dictionary<string, object>();
dic["code"] = "AA001";
dic["name"] = "John Smith";
dic["date_register"] = DateTime.Now;
dic["tel"] = "1298343223";
dic["email"] = "[email protected]";
dic["status"] = 1;
m.Insert("player", dic);
int newid = m.LastInsertId;Performs UPDATE by using dictionary.
Note: The dictionary values will be inserted as parameterized values
For updating table that has one primary key. The parameters:
m.Update(tablename, dictionary, primary key column name, id);Generate the dictionary entries from the Helper App.
Remove the "id" dictionary entry:
dic["id"] =Paste it at the code block, fill the value and execute the Update command:
Dictionary<string, object> dic = new Dictionary<string, object>();
dic["code"] = "AA001";
dic["name"] = "John Smith";
dic["date_register"] = DateTime.Now;
dic["tel"] = "1298343223";
dic["email"] = "[email protected]";
dic["status"] = 1;
m.Update("player", dic, "id", 1);For updating table that has multiple primary keys or multiple reference column. The parameters:
m.Update(tablename, dictionary data, dictionary reference data);Example:
// data
Dictionary<string, object> dic = new Dictionary<string, object>();
dic["code"] = "AA001";
dic["name"] = "John Smith";
dic["date_register"] = DateTime.Now;
dic["tel"] = "1298343223";
dic["email"] = "[email protected]";
dic["status"] = 1;
// update condition / referrence column data
Dictionary<string, object> dicCond = new Dictionary<string, object>();
dicCond["year"] = 2022;
dicCond["team_id"] = 1;
m.Update("player_team", dic, dicCond);Performs INSERT & UPDATE by using dictionary.
Note: The dictionary values will be inserted as parameterized values
This is especially useful when the table has multiple primary keys and no auto-increment field.
Insert > if the primary keys are not existed
Update it > if the primary keys existed.
First, generate the dictionary entries:
Next, generate the update column list:
Paste it at the code block and runs the Insert Update method:
List<string> lstUpdateCol = new List<string>();
lstUpdateCol.Add("team_id");
lstUpdateCol.Add("score");
lstUpdateCol.Add("level");
lstUpdateCol.Add("status");
using (MySqlConnection conn = new MySqlConnection(config.ConnString))
{
using (MySqlCommand cmd = new MySqlCommand())
{
cmd.Connection = conn;
conn.Open();
MySqlExpress m = new MySqlExpress(cmd);
// data
Dictionary<string, object> dic = new Dictionary<string, object>();
dic["year"] = 2022;
dic["player_id"] = 1;
dic["team_id"] = 1;
dic["score"] = 10m;
dic["level"] = 1;
dic["status"] = 1;
m.InsertUpdate("player_team", dic, lstUpdateCol);
conn.Close();
}
}string name = "James O'Brien";
// parameters
Dictionary<string, object> dicParam = new Dictionary<string, object>();
dicParam["@vname"] = m.GetLikeString(name);
List<obPlayer> lst = m.GetObjectList<obPlayer>("select * from player where name like @vname;", dicParam);Dictionary<string, object> dicParam = new Dictionary<string, object>();
dicParam["@vName"] = "James O'Brien";
dicParam["@vCode"] = "AA001";
m.Execute("delete from player where name=@vName or code=@vCode;", dicParam);Happy coding.