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This article mainly introduces the relevant knowledge of "what are the requirements of mysql foreign key constraints". The editor shows you the operation process through actual cases, the operation method is simple and fast, and it is practical. I hope this article "what are the requirements of mysql foreign key constraints" can help you solve the problem.

1. Establish a foreign key on the table, and the primary table should exist first.

2. A table can establish multiple foreign key constraints.

3. The foreign key column of the slave table must point to the primary key column of the primary table.

4. the foreign key column of the slave table can be different from the column name referenced by the master table, but the data type must be the same.

Example

Mysql > show create table students\ gateway * 1. Row * * Table: studentsCreate Table: CREATE TABLE `students` (`id` int (11) NOT NULL AUTO_INCREMENT, `uid` int (11) NOT NULL, `name` varchar (6) NOT NULL, PRIMARY KEY (`id`), KEY `uid` (`uid`) CONSTRAINT `students_ibfk_ 1` FOREIGN KEY (`uid`) REFERENCES `class` (`xuehao`) ON DELETE CASCADE ON UPDATE CASCADE) ENGINE=InnoDB DEFAULT CHARSET=utf8 's content on "what are the requirements for mysql foreign key constraints"? Thank you for your reading. If you want to know more about the industry, you can follow the industry information channel. The editor will update different knowledge points for you every day.

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