List most referenced tables (by FK) in Redshift

Query below lists tables that are most referenced by other tables with foreign keys.

See also:

Query

select pk_tco.table_schema || '.' || pk_tco.table_name as table_name,
       count(*) as references,
       count(distinct fk_tco.table_name) as referencing_tables
from information_schema.referential_constraints rco
join information_schema.table_constraints fk_tco
     on rco.constraint_name = fk_tco.constraint_name
     and rco.constraint_schema = fk_tco.table_schema
join information_schema.table_constraints pk_tco
     on rco.unique_constraint_name = pk_tco.constraint_name
     and rco.unique_constraint_schema = pk_tco.table_schema
group by 1
order by count(*) desc;

Columns

  • table_name - name of the table with schema name
  • references - number of foreign keys referencing to this table
  • referencing_tables - number of different tables referencing to this table

Rows

  • One row represents one table in a database
  • Scope of rows: tables being used in foreign keys as primary key table
  • Ordered by number of foregin keys descending

Sample results

dbo.language table is referenced 2 times from one table.

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