Where is the foreign key clause specified in MySQL?

Where is the foreign key clause specified in MySQL?

The FOREIGN KEY clause is specified in the child table. The parent and child tables must use the same storage engine. They must not be TEMPORARY tables. In MySQL 8.0, creation of a foreign key constraint requires the REFERENCES privilege for the parent table.

Can a table in a foreign key relationship be changed?

A table in a foreign key relationship cannot be altered to use another storage engine. To change the storage engine, you must drop any foreign key constraints first. A foreign key constraint cannot reference a virtual generated column.

Can a child table record have a foreign key reference?

MySQL supports foreign key references between one column and another within a table. (A column cannot have a foreign key reference to itself.) In these cases, a “child table record” refers to a dependent record within the same table.

What are the rules for foreign key constraint naming?

Foreign key constraint naming is governed by the following rules: The CONSTRAINT symbol value is used, if defined. If the CONSTRAINT symbol clause is not defined, or a symbol is not included following the CONSTRAINT keyword, a constraint name name is generated automatically.

Which is a valid partitioning key in MySQL?

When partitioning by [ LINEAR ] KEY, it is possible to use columns of any valid MySQL data type other than TEXT or BLOB as partitioning keys, because the internal key-hashing functions produce the correct data type from these types. For example, the following two CREATE TABLE statements are valid:

Can a table contain a foreign key reference?

No InnoDB table definition may contain a foreign key reference to a user-partitioned table; no InnoDB table with user-defined partitioning may contain columns referenced by foreign keys. The scope of the restrictions just listed includes all tables that use the InnoDB storage engine.

Can a column be partitioned by a linear key?

There are two exceptions to this restriction: When partitioning by [ LINEAR ] KEY, it is possible to use columns of any valid MySQL data type other than TEXT or BLOB as partitioning keys, because the internal key-hashing functions produce the correct data type from these types.

What is the syntax error around foreign key assignment?

Update the question so it’s on-topic for Database Administrators Stack Exchange. Closed 2 years ago. I put the following into DB Fiddle in an attempt to debug it. The error is below This is my first attempt at foreign keys. What am I doing wrong above?

Can a column have a foreign key reference to itself?

(A column cannot have a foreign key reference to itself.) In these cases, a “child table record” refers to a dependent record within the same table. MySQL requires indexes on foreign keys and referenced keys so that foreign key checks can be fast and not require a table scan.