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Mysql can parse the foreign key syntax for the myisam table type (meaning no error message will be raised if it encounters an fk definition), making migration from other database products or table engines easier because you do not have to edit the create table statements to remove them.
4 lut 2017 · It's a little bit of work, but you can do this using triggers, see e.g. here or here. Although you might want to consider changing your hosting site, because there is other stuff that you cannot do in MyISAM (probably most importantly transactions), and, in case that site doesn't support innodb not by choice but because it is too old, because a ...
The NDB storage engine requires an explicit unique key (or primary key) on any column referenced as a foreign key, as per the SQL standard. For storage engines that do not support foreign keys (such as MyISAM), MySQL Server parses and ignores foreign key specifications.
However, the older MyISAM storage engine does not include support for foreign keys. This means that MyISAM tables that are reverse engineered will not automatically have the relationship lines drawn between tables, making the database harder to understand.
You are advised to use foreign keys that reference only UNIQUE (including PRIMARY) and NOT NULL keys. For storage engines that do not support foreign keys (such as MyISAM), MySQL Server parses and ignores foreign key specifications.
Use the MyISAM storage engine for read-heavy workloads and applications that require full-text search capabilities. MyISAM storage engine doesn’t support some important features such as transactions and foreign keys, which are essential for data integrity in many applications.
MySQL FOREIGN KEY Constraint. The FOREIGN KEY constraint is used to prevent actions that would destroy links between tables. A FOREIGN KEY is a field (or collection of fields) in one table, that refers to the PRIMARY KEY in another table.
