Skip to content
Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works

primary key

The column that uniquely identifies each row in a table.

A primary key is a column (or set of columns) whose value is unique and not null for every row; foreign keys in other tables refer to it.

Examples

  • id INTEGER PRIMARY KEY in the tools table: inserting a second row with id 1 fails with a constraint error.

See also

SQL join database migration ORM
Read the full section →