Constraints

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Documentation / DuckDB Extension / Advanced Features

Constraints

DuckLake has limited support for constraints. The only constraint type that is currently supported is NOT NULL. It does not support PRIMARY KEY, FOREIGN KEY, UNIQUE or CHECK constraints.

Examples

Define a column as not accepting NULL values using the NOT NULL constraint.

CREATE TABLE tbl (col INTEGER NOT NULL);

Add a NOT NULL constraint to an existing column of an existing table.

ALTER TABLE tbl ALTER col SET NOT NULL;

Drop a NOT NULL constraint from a table.

ALTER TABLE tbl ALTER col DROP NOT NULL;