MySQL

DDL API Reference

MySQL Data Definition Language for creating and altering tables, indexes and constraints.

By EZ4Code TeamLast updated: 2026-08-01

DDL

Statements that define or modify the database schema.

CREATE TABLE [IF NOT EXISTS] tbl (col type [constraints], ...)

Creates a new table with the given columns and table-level constraints.

Returns: void

ALTER TABLE tbl ADD [COLUMN] col type | DROP COLUMN col | MODIFY col type

Adds, removes or modifies columns and constraints on an existing table.

Returns: void

CREATE [UNIQUE] INDEX name ON tbl (col, ...) [USING BTREE]

Creates a secondary index on one or more columns to speed up lookups; UNIQUE enforces uniqueness.

Returns: void

CONSTRAINT name PRIMARY KEY|FOREIGN KEY|UNIQUE|CHECK (cols)

Table-level constraint clause enforcing integrity rules on one or more columns.

Returns: void