Goal This query audits the database schema to enforce a uniform naming strategy for CHECK constraints. It identifies inconsistencies where constraints enforcing identical Boolean expressions are named using disparate patterns across different tables. To isolate the naming pattern from specific object identifiers, the query normalizes the constraint names by substituting the actual table name with the generic token TABLE. This allows it to detect violations of the "Clean Code" principle of consistency—flagging cases where the same logical rule is implemented with a specific naming convention in one context (e.g., chk_TABLE_column) but a different convention in another (e.g., TABLE_column_check).
Notes The query assumes that snake_case naming style is used. The query only considers CHECK constraints that are associated with a base table. The query only considers constraints that have the same syntax. The same rule could be enforced by different CHECK constraint Boolean expressions. The names of such constraints should follow the same pattern but the query does not check that. In case of the string_agg function, the line break (br) tag is used as a part of the separator for the better readability in case the query result is displayed in a web browser.
Type Problem detection (Each row in the result could represent a flaw in the design)
Reliability Medium (Medium number of false-positive results)
License MIT (opens in new tab)
Data Source system catalog only
SQL Query 
with ck as (select 
o.conname,
(select nspname from pg_namespace where oid=c.relnamespace) as target_schema,
c.relname as target_table, 
c.oid as target_table_oid,
unnest(o.conkey) AS target_col,
substring(pg_get_constraintdef(o.oid),7) as consrc
from pg_constraint o inner join pg_class c on c.oid = o.conrelid
where o.contype = 'c'),
ck_names as (select regexp_replace(ck.conname::text, (ck.target_table || '(?=_)'),'T A B L E','gi') as conname_pattern, ck.target_schema, ck.target_table, string_agg(a_target.attname, ', ' ORDER BY a_target.attname) as target_col, ck.consrc
from ck inner join pg_attribute a_target on ck.target_col = a_target.attnum and ck.target_table_oid = a_target.attrelid and a_target.attisdropped = false
group by conname, ck.target_schema, ck.target_table, ck.consrc)
SELECT consrc, string_agg(target_schema || '.' || target_table || '.(' || target_col || ').' || conname_pattern, ',<br>' ORDER BY target_schema, target_table) AS constraints
FROM ck_names
GROUP BY consrc
HAVING Count(DISTINCT conname_pattern)>1
ORDER BY consrc;

Collections

This query belongs to the following collections:

Find problems automatically

Queries, that results point to problems in the database. Each query in the collection produces an initial assessment. However, a human reviewer has the final say as to whether there is a problem or not .

NameDescription
Find problems automaticallyQueries, that results point to problems in the database. Each query in the collection produces an initial assessment. However, a human reviewer has the final say as to whether there is a problem or not .

Categories

This query is classified under the following categories:

CHECK constraints

Queries of this category provide information about CHECK constraints.

Inconsistencies

Queries of this catergory provide information about inconsistencies of solving the same problem in different places.

Naming

Queries of this category provide information about the style of naming.

NameDescription
CHECK constraintsQueries of this category provide information about CHECK constraints.
InconsistenciesQueries of this catergory provide information about inconsistencies of solving the same problem in different places.
NamingQueries of this category provide information about the style of naming.

Further reading and related materials:

The corresponding code smell in case of cleaning code is "G11: Inconsistency". (Robert C. Martin, Clean Code)
Reference
The corresponding code smell in case of cleaning code is "G11: Inconsistency". (Robert C. Martin, Clean Code)