Convert ADD CONSTRAINT SQL into OpCreateConstraint operations for foreign keys

[ryanslade]

Supports translating statements in the following forms:

ALTER TABLE foo ADD CONSTRAINT fk_bar_cd FOREIGN KEY (a, b) REFERENCES bar (c, d)
ALTER TABLE foo ADD CONSTRAINT fk_bar_cd FOREIGN KEY (a, b) REFERENCES bar (c, d) ON DELETE NO ACTION
ALTER TABLE foo ADD CONSTRAINT fk_bar_cd FOREIGN KEY (a, b) REFERENCES bar (c, d) ON DELETE RESTRICT
ALTER TABLE foo ADD CONSTRAINT fk_bar_cd FOREIGN KEY (a, b) REFERENCES bar (c, d) ON DELETE SET DEFAULT
ALTER TABLE foo ADD CONSTRAINT fk_bar_cd FOREIGN KEY (a, b) REFERENCES bar (c, d) ON DELETE SET NULL
ALTER TABLE foo ADD CONSTRAINT fk_bar_c FOREIGN KEY (a) REFERENCES bar (c)
ALTER TABLE schema.foo ADD CONSTRAINT fk_bar_c FOREIGN KEY (a) REFERENCES schema.bar (c)

The following fall back to raw SQL:

ALTER TABLE foo ADD CONSTRAINT fk_bar_cd FOREIGN KEY (a, b) REFERENCES bar (c, d) ON UPDATE RESTRICT;
ALTER TABLE foo ADD CONSTRAINT fk_bar_cd FOREIGN KEY (a, b) REFERENCES bar (c, d) ON UPDATE CASCADE;
ALTER TABLE foo ADD CONSTRAINT fk_bar_cd FOREIGN KEY (a, b) REFERENCES bar (c, d) ON UPDATE SET NULL;
ALTER TABLE foo ADD CONSTRAINT fk_bar_cd FOREIGN KEY (a, b) REFERENCES bar (c, d) ON UPDATE SET DEFAULT;
ALTER TABLE foo ADD CONSTRAINT fk_bar_cd FOREIGN KEY (a, b) REFERENCES bar (c, d) MATCH FULL;

Part of #504

[andrew-farries]

Nice 👍 Just one comment

[andrew-farries]

There's a doc comment for this function that could be updated now that this function also handles conversion of foreign key constraints.