June 28, 2018
Mysql: 外键约束, CASCADE、SET NULL、RESTRICT、NO ACTION分析和作用, Cannot delete or update a parent row: a foreign key constraint fails
MySQL有两种常用的引擎类型：MyISAM和InnoDB。目前只有InnoDB引擎类型支持外键约束。InnoDB中外键约束定义的语法如下：
ALTER TABLE tbl_name
ADD [CONSTRAINT [symbol]] FOREIGN KEY
[index_name] (index_col_name, ...)
REFERENCES tbl_name (index_col_name,...)
[ON DELETE reference_option]
[ON UPDATE reference_option]
例如：
ALTER TABLE `user_resource` CONSTRAINT `FKEEAF1E02D8… Read More