Goal Find all CHECK constraints (except NOT NULL) that are associated with a base table or a foreign table column and use a regular expression. It is useful to enforce as many constraints at database level as possible. In this way one improves data quality as well as gives extra information to the database users (including the DBMS engines, development environments, and applications).
Notes The query also consideres regexp_like function that was added to PostgreSQL 15 and provides the same functionality as ~ and ~* operators.
Type General Overview of some aspect of the database.
License MIT (opens in new tab)
Data Source INFORMATION_SCHEMA only
SQL Query 
WITH checks AS (SELECT ccu.table_schema, ccu.table_name, t.table_type, ccu.column_name, cc.check_clause, cc.constraint_name, 'TABLE CHECK' AS check_type, NULL AS domain_schema, NULL AS domain_name
FROM INFORMATION_SCHEMA.constraint_column_usage AS ccu INNER JOIN INFORMATION_SCHEMA.check_constraints AS cc USING (constraint_schema, constraint_name)
INNER JOIN INFORMATION_SCHEMA.tables AS t USING (table_schema, table_name)
WHERE cc.check_clause NOT LIKE '%IS NOT NULL' AND 
ccu.table_schema NOT IN (SELECT schema_name
FROM INFORMATION_SCHEMA.schemata
WHERE schema_name<>'public' AND
schema_owner='postgres' AND schema_name IS NOT NULL)
UNION SELECT cdu.table_schema, cdu.table_name, t.table_type, cdu.column_name, cc.check_clause, cc.constraint_name, 'DOMAIN CHECK' AS check_type, cdu.domain_schema, cdu.domain_name
FROM INFORMATION_SCHEMA.column_domain_usage AS cdu INNER JOIN INFORMATION_SCHEMA.tables AS t USING (table_schema, table_name)
INNER JOIN INFORMATION_SCHEMA.domain_constraints AS dc USING (domain_schema, domain_name)
INNER JOIN INFORMATION_SCHEMA.check_constraints AS cc USING (constraint_schema, constraint_name)
WHERE t.table_type IN ('BASE TABLE','FOREIGN') AND cc.check_clause NOT LIKE '%IS NOT NULL'  AND 
cdu.table_schema NOT IN (SELECT schema_name
FROM INFORMATION_SCHEMA.schemata
WHERE schema_name<>'public' AND
schema_owner='postgres' AND schema_name IS NOT NULL))
SELECT table_schema, table_name, table_type, column_name, check_clause, constraint_name, check_type, domain_schema, domain_name 
FROM checks
WHERE check_clause~*'(([[:space:]]|!)~[*]{0,1}[[:space:]]|regexp_like[(])'
ORDER BY table_schema, table_name,column_name;

Collections

This query belongs to the following collections:

Find problems by overview

Queries that results point to different aspects of database that might have problems. A human reviewer has to decide based on the results as to whether there are problems or not .

NameDescription
Find problems by overviewQueries that results point to different aspects of database that might have problems. A human reviewer has to decide based on the results as to whether there are problems or not .

Categories

This query is classified under the following categories:

CHECK constraints

Queries of this category provide information about CHECK constraints.

Regular expressions

Queries of this catergory provide information about the use of regular expressions.

NameDescription
CHECK constraintsQueries of this category provide information about CHECK constraints.
Regular expressionsQueries of this catergory provide information about the use of regular expressions.