DROP TABLE project_category; CREATE TABLE smoke_report_tag ( id INTEGER PRIMARY KEY AUTOINCREMENT, smoke_report INTEGER NOT NULL, tag TEXT DEFAULT '', CONSTRAINT 'fk_smoke_report_tag_smoke_report' FOREIGN KEY ('smoke_report') REFERENCES 'smoke_report' ('id') ON DELETE CASCADE ); CREATE INDEX i_project_smoke_tag_tag ON smoke_report_tag (tag); INSERT INTO smoke_report_tag (smoke_report, tag) SELECT id, category FROM smoke_report; DELETE FROM smoke_report_tag WHERE tag IS NULL;