prepareAlterColumnsMysql() — drizzle-orm Function Reference

Architecture documentation for the prepareAlterColumnsMysql() function in jsonStatements.ts from the drizzle-orm codebase.

Function typescript DrizzleKit SchemaDiffer calls 1 called by 2

Entity Profile

DrizzleKit→ SchemaDiffer→ prepareAlterColumnsMysql() — drizzle-orm Function Reference

Dependency Diagram

graph TD
  7b55cf7f_6d2b_2fa4_a8ff_81bae7f0b9c9["prepareAlterColumnsMysql()"]
  6139f734_8ada_c641_9fec_9a55cfdf376f["jsonStatements.ts"]
  7b55cf7f_6d2b_2fa4_a8ff_81bae7f0b9c9 -->|defined in| 6139f734_8ada_c641_9fec_9a55cfdf376f
  a5972ffc_ff1b_9523_2495_5373af710e65["applyMysqlSnapshotsDiff()"]
  a5972ffc_ff1b_9523_2495_5373af710e65 -->|calls| 7b55cf7f_6d2b_2fa4_a8ff_81bae7f0b9c9
  d4992b27_bf78_8099_5134_750cef1c518c["applySingleStoreSnapshotsDiff()"]
  d4992b27_bf78_8099_5134_750cef1c518c -->|calls| 7b55cf7f_6d2b_2fa4_a8ff_81bae7f0b9c9
  5fbcc7ce_945a_7e2d_e12d_559fa5000971["warning()"]
  7b55cf7f_6d2b_2fa4_a8ff_81bae7f0b9c9 -->|calls| 5fbcc7ce_945a_7e2d_e12d_559fa5000971
  style 7b55cf7f_6d2b_2fa4_a8ff_81bae7f0b9c9 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

drizzle-kit/src/jsonStatements.ts lines 1362–1715

export const prepareAlterColumnsMysql = (
	tableName: string,
	schema: string,
	columns: AlteredColumn[],
	// TODO: remove?
	json1: CommonSquashedSchema,
	json2: CommonSquashedSchema,
	action?: 'push' | undefined,
): JsonAlterColumnStatement[] => {
	let statements: JsonAlterColumnStatement[] = [];
	let dropPkStatements: JsonAlterColumnDropPrimaryKeyStatement[] = [];
	let setPkStatements: JsonAlterColumnSetPrimaryKeyStatement[] = [];

	for (const column of columns) {
		const columnName = typeof column.name !== 'string' ? column.name.new : column.name;

		const table = json2.tables[tableName];
		const snapshotColumn = table.columns[columnName];

		const columnType = snapshotColumn.type;
		const columnDefault = snapshotColumn.default;
		const columnOnUpdate = 'onUpdate' in snapshotColumn ? snapshotColumn.onUpdate : undefined;
		const columnNotNull = table.columns[columnName].notNull;

		const columnAutoIncrement = 'autoincrement' in snapshotColumn
			? snapshotColumn.autoincrement ?? false
			: false;

		const columnPk = table.columns[columnName].primaryKey;

		if (column.autoincrement?.type === 'added') {
			statements.push({
				type: 'alter_table_alter_column_set_autoincrement',
				tableName,
				columnName,
				schema,
				newDataType: columnType,
				columnDefault,
				columnOnUpdate,
				columnNotNull,
				columnAutoIncrement,
				columnPk,
			});
		}

		if (column.autoincrement?.type === 'changed') {
			const type = column.autoincrement.new
				? 'alter_table_alter_column_set_autoincrement'
				: 'alter_table_alter_column_drop_autoincrement';

			statements.push({
				type,
				tableName,
				columnName,
				schema,
				newDataType: columnType,
				columnDefault,
				columnOnUpdate,
				columnNotNull,
				columnAutoIncrement,
				columnPk,
			});
		}

		if (column.autoincrement?.type === 'deleted') {
			statements.push({
				type: 'alter_table_alter_column_drop_autoincrement',
				tableName,
				columnName,
				schema,
				newDataType: columnType,
				columnDefault,
				columnOnUpdate,
				columnNotNull,
				columnAutoIncrement,
				columnPk,
			});
		}
	}

	for (const column of columns) {