-- Insert Default category
INSERT OR IGNORE INTO categories(_id, name, sort, flags) VALUES (0, "", -1, 0);
-- Disallow deletion of default category
CREATE TRIGGER IF NOT EXISTS system_category_delete_trigger BEFORE DELETE
ON categories
BEGIN SELECT CASE
    WHEN old._id <= 0 THEN
        RAISE(ABORT, "System category can't be deleted")
    END;
END;