WebOct 19, 2024 · Must reference PRIMARY KEY in primary table. Foreign key column and constraint column should have matching data types. Records cannot be inserted in child table if corresponding record in master table do not exist. Records of master table cannot be deleted if corresponding records in child table exits. SQL Foreign key At column level : … WebThe names of constraints, indexes, keys... must be unique. The message is clear: Duplicate foreign key constraint name... is indicating that the name of the foreign key idPersona already exists you can't use it again. You should use a naming convention also for the names of your keys, indexes, etc.
Foreign Key Constraint in SQL Server - Dot Net Tutorials
WebLaravel Version 10.1.5 PHP Version 8.1 Database Driver & Version MySQL Description If you chain ->index() onto a schema builder migration that also has a foreign id constraint, it appears to name the constraint 1. This name will be used ... iota tangle example
[Solved] mysql Error 1826: Duplicate foreign key constraint
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 … Web[CONSTRAINT [symbol]] FOREIGN KEY [index_name] (index_col_name, ...) REFERENCES tbl_name (index_col_name,...) Which says index_name represents a foreign key ID. If given, this is ignored if an index for the foreign key is defined explicitly. Otherwise, if MySQL creates an index for the foreign key, it uses index_name for the … WebMay 25, 2024 · show index from borrow_order 写查询条件时,索引中在前面的字段先查。 或者根据查询来建联合索引,就在建立索引时,把先查的字段写在前面,如本例中的 status 。 3. 存在同名索引时会报错:Duplicate key name 4. 删除: ALTER TABLE borrow_order DROP INDEX idx_status_stitution 本文参与 腾讯云自媒体分享计划 ,欢迎热爱写作的你 … ontrac rates