WebCREATE TABLE t1 ( a integer PRIMARY KEY, b integer, c integer, FOREIGN KEY (b, c) REFERENCES other_table (c1, c2)); Of course, the number and type of the constrained columns need to match the number and type of the referenced columns. You can assign your own name for a foreign key constraint, in the usual way. Web如果需要命名 foreign key 约束,以及为多个列定义 foreign key 约束,请使用下面的 sql 语法: MySQL / SQL Server / Oracle / MS Access: CREATE TABLE Orders ( Id_O int …
mysql加外键报错 ERROR 1826: Duplicate foreign key constraint name …
WebJul 6, 2024 · 1. Mismatched data types. When you’re using a foreign key to reference a column in another table, the datatypes of both tables have to be the same. For example, … WebSep 14, 2016 · That's why you are getting the duplicate foreign key constraint name when you are trying to execute this: ADD CONSTRAINT `bid_ibfk_3` FOREIGN KEY … dateonly serialization
"Duplicate FOREIGN KEY constraint name" error when using …
WebMay 19, 2024 · 1 On Postgres 9.6, I have a table where a foreign key constraint and a unique constraint have the same name (ultimately due to long distinct names being silently truncated to 63 chars). I'm trying to resolve this name conflict through ALTER TABLE RENAME CONSTRAINT, but that yields an error: table x has multiple constraints … WebAug 8, 2013 · 名称可以加,但不能重复。 同一数据库中不能重复。 yhm2046 2013-08-08 搞定了,原来是语法错误,key后面不能加表名,否则会当成外键名称,所以会爆重复错误! 正确写法如下: alter table t_user add constraint u_paid_id2p_id foreign key (u_paid_id) references t_paid (p_id) on delete cascade on update cascade; WebFOREIGN KEY 约束用于预防破坏表之间连接的动作。 FOREIGN KEY 约束也能防止非法数据插入外键列,因为它必须是它指向的那个表中的值之一。 SQL FOREIGN KEY Constraint on CREATE TABLE 下面的 SQL 在 "Orders" 表创建时为 "Id_P" 列创建 FOREIGN KEY: MySQL: CREATE TABLE Orders ( Id_O int NOT NULL, OrderNo int NOT NULL, Id_P … bizhub waste toner box installation error