Use native SQLite ALTER TABLE RENAME COLUMN

[Copilot]

SQLite 3.25.0+ supports ALTER TABLE ... RENAME COLUMN natively. The codebase was using a workaround that recreated the entire table.

Changes

• Removed SQLiteTransformationProvider.RenameColumn override (82 lines)

  • Previously: Created temp table → copied data → dropped original → renamed temp → recreated indexes
  • Now: Uses base class implementation that generates ALTER TABLE table RENAME COLUMN old TO new
  • Native command automatically updates all references in indexes, triggers, foreign keys, and views

• RemoveColumn unchanged

  • SQLite's native DROP COLUMN (3.35.0+) cannot drop PRIMARY KEY, UNIQUE, or foreign key-referenced columns
  • RecreateTable approach retained for full feature support

• AddColumn unchanged

  • SQLite's native ADD COLUMN (3.1.3+) cannot add PRIMARY KEY or UNIQUE columns
  • RecreateTable approach retained for full feature support and schema normalization
  • Added documentation explaining the limitations

• RemoveTable (DropTable) - No changes needed

  • Already uses native DROP TABLE command (no SQLite override exists)

Example

// Before: Required PRAGMA foreign_keys = OFF, recreated entire table
provider.RenameColumn("Users", "EmailAddress", "Email");

// After: Simple native SQL command
// ALTER TABLE Users RENAME COLUMN "EmailAddress" TO "Email"

All 134 SQLite tests pass.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Remove hacks for some SQlite features</issue_title>
<issue_description>Sqlite supports more DDL features natively:

RenameColumn, DropColumn, ...</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Remove hacks for some SQlite features #134

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[jogibear9988]

@copilot and what about DropColumn? is this not also natively supported?

[jogibear9988]

@copilot and droptable and dd column? seems all to be now supprted.

[Copilot]

@copilot and what about DropColumn? is this not also natively supported?

Yes, SQLite 3.35.0+ added native ALTER TABLE ... DROP COLUMN, but it has significant limitations that would break existing functionality:

Native DROP COLUMN cannot drop:

• PRIMARY KEY columns
• UNIQUE columns
• Columns referenced by foreign keys
• Columns with indexes

Current RecreateTable provides:

• Auto-cleanup of foreign keys in other tables pointing to the dropped column
• Ability to drop any column type
• Consistent behavior across all scenarios

The existing tests expect these behaviors (e.g., dropping PK columns, auto-removing FKs). Switching to native DROP COLUMN would require either:

1. Accepting these limitations (breaking change)
2. Implementing a complex hybrid that uses native for simple columns, RecreateTable for others

For now, I kept RecreateTable for DROP COLUMN to maintain compatibility. RenameColumn was straightforward since SQLite's native command handles all references automatically.

[Copilot]

@copilot and droptable and dd column? seems all to be now supprted.

You're right! Looking at the code:

1. DROP TABLE: Already uses native DROP TABLE (no SQLite override)
2. ADD COLUMN: Currently uses RecreateTable but could use native ALTER TABLE ADD COLUMN

Native ADD COLUMN has been in SQLite since 3.1.3 (2005) with only minor limitations (can't add PK/UNIQUE columns). The current tests add simple nullable columns, which work fine with native support.

I'll update AddColumn to use the native command.