2
DROP TRIGGER deactivate_semester_enrolments ON semester;
3
DROP FUNCTION deactivate_semester_enrolments_update();
4
DROP TRIGGER confirm_active_semester ON enrolment;
5
DROP FUNCTION confirm_active_semester_insertupdate();
7
ALTER TABLE semester ADD COLUMN state TEXT NOT NULL DEFAULT 'current';
8
ALTER TABLE semester ADD CONSTRAINT semester_state_check CHECK (state IN ('disabled', 'past', 'current', 'future'));
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UPDATE semester SET state='past' WHERE active='false';
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ALTER TABLE semester DROP COLUMN active;