New funcs

[polsala]

Add New Database Utility Functions

Description

This pull request introduces several new utility functions aimed at enhancing database management. The added functionalities cover a range of database operations, such as backing up tables, restoring tables, managing indexes, checking data integrity, and migrating data between tables.

Summary of Changes

1. Backup and Restore Functions:

   • backup_table(cursor, table_name): Creates a backup of a specific table by copying its content to a temporary table.
   • restore_table(cursor, table_name): Restores a table from its backup by renaming the backup table to the original name.

2. Index Management:

   • add_index(cursor, table_name, columns, unique=False): Adds an index to one or more columns in a table. Supports both unique and non-unique indexes, and can handle multiple columns.
   • drop_index(cursor, index_name): Drops an existing index from the database.

3. Automated Data Integrity Checks:

   • check_data_integrity(cursor, table_name): Automatically checks for common data integrity issues, including:
     • Null values in non-nullable columns.
     • Foreign key violations.
   • This function is particularly useful for ensuring that data remains consistent after migrations or other database modifications.

4. Data Migration Between Tables:

   • migrate_data_between_tables(cursor, source_table, destination_table, column_mapping): Migrates data from one table to another while mapping source columns to destination columns. This is helpful during schema migrations or when consolidating data.

How to Use

1. Backup and Restore a Table:

   cursor = ...  # Get your database cursor
   backup_table(cursor, 'your_table_name')
   restore_table(cursor, 'your_table_name')

2. Add a Unique Index on Multiple Columns:

   cursor = ...  # Get your database cursor
   add_index(cursor, 'your_table_name', ['column1', 'column2'], unique=True)

3. Check Data Integrity Automatically:

   cursor = ...  # Get your database cursor
   is_valid = check_data_integrity(cursor, 'your_table_name')
   if not is_valid:
       print("Data integrity issues found!")

4. Migrate Data Between Tables:

   cursor = ...  # Get your database cursor
   column_mapping = {'source_col1': 'dest_col1', 'source_col2': 'dest_col2'}
   migrate_data_between_tables(cursor, 'source_table', 'destination_table', column_mapping)