我有两张这样的桌子:
DROP TABLE IF EXISTS schemas.book;
DROP TABLE IF EXISTS schemas.category;
DROP SCHEMA IF EXISTS schemas;
CREATE SCHEMA schemas;
CREATE TABLE schemas.category (
id BIGSERIAL PRIMARY KEY,
name VARCHAR NOT NULL,
UNIQUE(name)
);
CREATE TABLE schemas.book (
id BIGSERIAL PRIMARY KEY,
published DATE NOT NULL,
category_id BIGINT NOT NULL REFERENCES schemas.category ON DELETE CASCADE ON UPDATE CASCADE,
author VARCHAR NOT NULL,
name VARCHAR NOT NULL,
UNIQUE(published, author, name),
FOREIGN KEY(category_id) REFERENCES schemas.category (id)
);
所以逻辑很简单，在用户删除了x类下的所有书籍后，x从CAT中删除，我try 了上面的方法，但不起作用，在我清理了table book后，table category仍然填充，怎么了？