我尝试为postgresql创建代码
CREATE TABLE kaart (
kaartid integer NOT NULL,
naam character varying,
saldo real,
kaarthouderid integer
);
CREATE TABLE kaart_product (
kaartkaartid integer,
productid2 integer
);
CREATE TABLE kaarthouder (
id integer NOT NULL,
naam character varying(255),
naw character varying(255),
geslacht "char"
);
CREATE TABLE product (
naam character varying,
id integer NOT NULL
);
ALTER TABLE ONLY kaart
ADD CONSTRAINT kaart_pkey PRIMARY KEY (kaartid);
ALTER TABLE ONLY kaarthouder
ADD CONSTRAINT kaarthouder_pkey PRIMARY KEY (id);
ALTER TABLE ONLY product
ADD CONSTRAINT product_pkey PRIMARY KEY (id);
ALTER TABLE ONLY kaart
ADD CONSTRAINT kaartco FOREIGN KEY (kaartid) REFERENCES kaarthouder(id) ON UPDATE CASCADE ON DELETE CASCADE;
ALTER TABLE ONLY kaart_product
ADD CONSTRAINT kaartkaartidco FOREIGN KEY (kaartkaartid) REFERENCES kaart(kaartid) ON UPDATE CASCADE ON DELETE CASCADE;
ALTER TABLE ONLY kaart_product
ADD CONSTRAINT productidco FOREIGN KEY (kaartkaartid) REFERENCES product(id) ON UPDATE CASCADE ON DELETE CASCADE;
INSERT INTO kaart VALUES (1, 'Sander',50.00 ,1);
INSERT INTO kaart_product VALUES (1,1);
INSERT INTO kaarthouder VALUES (1, 'Sander','test,testing','man');
INSERT INTO product VALUES ('studentenproduct',1);
但每当我尝试运行它时,它会给我这个错误:
23503:在表“kaart”上插入或更新违反外键约束“kaartco”
但我真的不知道为什么会发生这种情况,因为它与其下面的其他外键相同
有人可以帮我解决这个问题吗?
您尝试链接到尚不存在的产品和kaart。
移动:
INSERT INTO kaart_product VALUES (1,1);
下面有两行:
INSERT INTO product VALUES ('studentenproduct',1);
那应该为你做的工作。尝试搜索谷歌的外键约束及其工作方式。