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Use native SQLite ALTER TABLE RENAME COLUMN #159

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Initial plan
Copilot Feb 6, 2026
6ad674b
Remove hack for SQLite RenameColumn - use native ALTER TABLE RENAME C…
Copilot Feb 6, 2026
59dd200
Document why AddColumn continues to use RecreateTable despite native …
Copilot Feb 6, 2026
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98 changes: 16 additions & 82 deletions src/Migrator/Providers/Impl/SQLite/SQLiteTransformationProvider.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -446,6 +446,12 @@ public override void RemoveColumn(string tableName, string column)
// In SQLite we need to recreate the table even if we only want to add, alter or drop a foreign key. So we not only recreate the table given
// as parameter but also the tables with FKs pointing to the column you want to remove.
// In order to perform it smoothly, the PRAGMA foreign keys should be set off.
//
// Note: SQLite 3.35.0+ added native ALTER TABLE ... DROP COLUMN support, but it has limitations:
// - Cannot drop PRIMARY KEY columns
// - Cannot drop UNIQUE columns
// - Cannot drop columns that are part of a foreign key or index
// Therefore, we continue using the RecreateTable approach for maximum compatibility and features.

var isPragmaForeignKeysOn = IsPragmaForeignKeysOn();

Expand Down Expand Up @@ -578,88 +584,9 @@ public override void RemoveColumn(string tableName, string column)
RecreateTable(sqliteInfoMainTable);
}

public override void RenameColumn(string tableName, string oldColumnName, string newColumnName)
{
if (!TableExists(tableName))
{
throw new Exception($"Table {tableName} does not exist");
}

var isPragmaForeignKeysOn = IsPragmaForeignKeysOn();

if (isPragmaForeignKeysOn)
{
throw new Exception($"{nameof(RenameColumn)} requires foreign keys off.");
}

// Due to old .Net versions we cannot use ThrowIfNullOrWhitespace
if (string.IsNullOrWhiteSpace(newColumnName))
{
throw new Exception("New column name is null or empty");
}

if (ColumnExists(tableName, newColumnName))
{
throw new MigrationException(string.Format("Table '{0}' has column named '{1}' already", tableName, newColumnName));
}

if (ColumnExists(tableName, oldColumnName))
{
var sqliteTableInfo = GetSQLiteTableInfo(tableName);

var columnMapping = sqliteTableInfo.ColumnMappings.First(x => x.OldName.Equals(oldColumnName, StringComparison.OrdinalIgnoreCase));
columnMapping.NewName = newColumnName;

var column = sqliteTableInfo.Columns.First(x => x.Name.Equals(oldColumnName, StringComparison.OrdinalIgnoreCase));
column.Name = newColumnName;

foreach (var foreignKey in sqliteTableInfo.ForeignKeys)
{
foreignKey.ChildColumns = [.. foreignKey.ChildColumns.Select(x => x.Equals(oldColumnName, StringComparison.OrdinalIgnoreCase) ? newColumnName : x)];
}

foreach (var index in sqliteTableInfo.Indexes)
{
index.KeyColumns = [.. index.KeyColumns.Select(x => x.Equals(oldColumnName, StringComparison.OrdinalIgnoreCase) ? newColumnName : x)];
}

foreach (var unique in sqliteTableInfo.Uniques)
{
unique.KeyColumns = [.. unique.KeyColumns.Select(x => x.Equals(oldColumnName, StringComparison.OrdinalIgnoreCase) ? newColumnName : x)];
}

RecreateTable(sqliteTableInfo);

var allTables = GetTables();

// Rename in foreign keys of depending tables
foreach (var allTablesItem in allTables)
{
if (allTablesItem == tableName)
{
continue;
}

var sqliteTableInfoOther = GetSQLiteTableInfo(allTablesItem);

foreach (var foreignKey in sqliteTableInfoOther.ForeignKeys)
{
if (foreignKey.ParentTable != tableName)
{
continue;
}

foreignKey.ParentColumns = foreignKey.ParentColumns.Select(x => x == oldColumnName ? newColumnName : x).ToArray();

RecreateTable(sqliteTableInfoOther);
}
}
}
else
{
throw new MigrationException(string.Format("The table '{0}' does not have a column named '{1}'", tableName, oldColumnName));
}
}
// SQLite 3.25.0+ supports ALTER TABLE ... RENAME COLUMN natively
// Use the base implementation which generates the correct SQL
// public override void RenameColumn removed to use base class implementation

public override void RemoveColumnDefaultValue(string tableName, string columnName)
{
Expand Down Expand Up @@ -900,6 +827,13 @@ public override void AddTable(string table, string engine, string columns)

public override void AddColumn(string table, Column column)
{
// SQLite 3.1.3+ (2005) supports ALTER TABLE ADD COLUMN natively, but with limitations:
// - Cannot add columns with PRIMARY KEY constraint
// - Cannot add columns with UNIQUE constraint
// - Cannot add columns with generated/expression default values
// The RecreateTable approach allows us to handle these cases and provides schema normalization.
// For simple column additions, native ADD COLUMN would work, but RecreateTable ensures consistency.

if (!TableExists(table))
{
throw new Exception("Table does not exist.");
Expand Down