The name of the catalog to which the constraint belongs. This value is always def . 

• CONSTRAINT_SCHEMA 

The name of the schema (database) to which the constraint belongs. 

• CONSTRAINT_NAME 

The name of the constraint. 

• TABLE_CATALOG 

The name of the catalog to which the table belongs. This value is always def . 

• TABLE_SCHEMA 

The name of the schema (database) to which the table belongs. 

• TABLE_NAME 

The name of the table that has the constraint. 

• COLUMN_NAME 

The name of the column that has the constraint. 

If the constraint is a foreign key, then this is the column of the foreign key, not the column that the foreign key references. 

• ORDINAL_POSITION 

The column’s position within the constraint, not the column’s position within the table. Column positions are numbered beginning with 1. 

• POSITION_IN_UNIQUE_CONSTRAINT 

NULL  for unique and primary-key constraints. For foreign-key constraints, this column is the ordinal position in key of the table that is being referenced. 

• REFERENCED_TABLE_SCHEMA 

The name of the schema referenced by the constraint. 

• REFERENCED_TABLE_NAME 

The name of the table referenced by the constraint. 

• REFERENCED_COLUMN_NAME 

The name of the column referenced by the constraint. 

Suppose that there are two tables name t1  and t3  that have the following definitions: 

CREATE TABLE t1 ( s1 INT, s2 INT, s3 INT, PRIMARY KEY(s3) ) ENGINE=InnoDB; 

