List foreign keys in MySQL database

The query below returns the foreign key constraints defined in the user databases (schemas).

Query

select concat(fks.constraint_schema, '.', fks.table_name) as foreign_table,
       '->' as rel,
       concat(fks.unique_constraint_schema, '.', fks.referenced_table_name)
              as primary_table,
       fks.constraint_name,
       group_concat(kcu.column_name
            order by position_in_unique_constraint separator ', ') 
             as fk_columns
from information_schema.referential_constraints fks
join information_schema.key_column_usage kcu
     on fks.constraint_schema = kcu.table_schema
     and fks.table_name = kcu.table_name
     and fks.constraint_name = kcu.constraint_name
-- where fks.constraint_schema = 'database name'
group by fks.constraint_schema,
         fks.table_name,
         fks.unique_constraint_schema,
         fks.referenced_table_name,
         fks.constraint_name
order by fks.constraint_schema,
         fks.table_name;

Note: if you need the information for a specific database (schema), then uncomment the where clause and provide your database name.

Columns

  • foreign_table - foreign table name with its database (schema) name
  • rel - relationship symbol implicating direction
  • primary_table - primary (referenced) table name with its database (schema) name
  • fk_constraint_name - foreign key constraint name
  • fk_columns - foreign key columns separated by ','

Rows

  • One row: represents one foreign key. If the foreign key consists of multiple columns (composite key), it is still represented as one row
  • Scope of rows: all foreign keys in the database (schema)
  • Ordered by: foreign database name and table name

Sample results

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