`information_schema.key_column_usage.constraint_name`

mysql

type: VARCHAR NULL

type: VARCHAR NOT NULL

5.7

type: NULL

Note:

Name of the constraint (PRIMARY for the primary key).

5.1-10.8

type: VARCHAR NOT NULL

Note:

Name of the constraint (PRIMARY for the primary key).

type: VARCHAR(64) NOT NULL

Note:

The name of the constraint.

4-6.1

type: SQL_IDENTIFIER NULL

Note:

Name of the constraint

10-15

type: SQL_IDENTIFIER

Note:

Name of the constraint

7.4-9.6

type: unknown

Note:

Name of the constraint.

1-21.2

type: NVARCHAR(128) NULL

Note:

Constraint name.