Enforce data rules using NOT NULL, UNIQUE, CHECK, PRIMARY KEY and FOREIGN KEY constraints.
CREATE TABLE team_members (team_id INTEGER, user_id INTEGER, PRIMARY KEY (team_id, user_id));SQL Constraints
Enforce data rules using NOT NULL, UNIQUE, CHECK, PRIMARY KEY and FOREIGN KEY constraints.
Syntax
CREATE TABLE ... (column type NOT NULL, UNIQUE (...), CHECK (...), FOREIGN KEY (...) REFERENCES ...);Examples
SQLite-oriented example; consult the relevant dialect manual.
CREATE TABLE team_members (team_id INTEGER, user_id INTEGER, PRIMARY KEY (team_id, user_id));Parameters, options and clauses
| Option / clause | Description |
|---|---|
Object name | Name a table, view, index, schema or database. |
Column definition | Specify column name, data type and default value. |
Constraints | Use NOT NULL, UNIQUE, CHECK, PRIMARY KEY or FOREIGN KEY as needed. |
IF EXISTS / IF NOT EXISTS | Make create/drop operations conditional where supported. |
CASCADE / RESTRICT | Control dependent-object handling where supported; verify before destructive changes. |
Dialect references
Review a command and its target before running it. Commands that alter files, services, accounts, disks, permissions or databases may be difficult to reverse. Test in a safe environment and keep backups.