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Constraints, defaults, keys

NOT NULL, DEFAULT, UNIQUE, PRIMARY KEY, CHECK — what is enforced.

Version
Latest
v0.1.0 · latest 1 min read
sqlsource
CREATE TABLE users (
  id BIGINT PRIMARY KEY,
  email TEXT NOT NULL UNIQUE,
  credit NUMERIC(12,2) NOT NULL DEFAULT 1000.00,
  status TEXT NOT NULL DEFAULT 'active',
  CONSTRAINT positive_credit CHECK (credit >= 0)
);
Constraint Enforcement in v0.1.0
NOT NULL write-time reject
DEFAULT <expr> applied on missing column (incl. now())
UNIQUE / PRIMARY KEY persistent B-tree authority + transient unique-gate reservation; conflict → error
CHECK (expr) evaluated per row
Foreign keys not enforced (see Compatibility)

Duplicate handling: unique/PK violations error the statement (and the transaction if in-txn). Empty results, not errors, signal no-match on reads. ON CONFLICT … DO NOTHING/DO UPDATE is the idempotent-write path — see INSERT.

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Next: Sequences and views CREATE SEQUENCE, nextval/currval, serial columns, and views. Playground Run the documented statements against the sample dataset. Architecture The layers underneath the documented surface.