DROP TABLE IF EXISTS product_question; -- DROP SEQUENCE IF EXISTS product_question_product_question_id_seq; -- CREATE SEQUENCE product_question_product_question_id_seq; CREATE TABLE product_question ( "product_question_id" int PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY, -- SERIAL PRIMARY KEY "product_id" int check ("product_id" > 0) NOT NULL, "user_id" int check ("user_id" >= 0) NOT NULL DEFAULT 0, "author" varchar(64) NOT NULL, "content" text NOT NULL, "status" smallint NOT NULL DEFAULT 0, "parent_id" int check ("parent_id" >= 0) NOT NULL DEFAULT 0, "created_at" timestamp(0) NOT NULL DEFAULT now(), "updated_at" timestamp(0) NOT NULL DEFAULT now() -- PRIMARY KEY("product_question_id") ); CREATE INDEX "product_question_product_id" ON product_question ("product_id"); SELECT setval('product_question_product_question_id_seq', 5, true); -- last inserted id by sample data