This query identifies inconsistencies in two-column CHECK constraints across the database. Specifically, it flags cases where different tables share the exact same pair of columns, but the logical expressions governing them differ. For example, one table might enforce last_change_time >= reg_time, while another strictly enforces last_change_time > reg_time. Highlighting these discrepancies helps ensure uniform data validation rules.
Type
Problem detection (Each row in the result could represent a flaw in the design)
If the constraints have to enforce the same rule in case of different tables, then try to use the same Boolean expression.
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'
and cardinality(o.conkey)=2),
ck_names as (select ck.conname, ck.target_schema, ck.target_table, ck.consrc, string_agg(a_target.attname, ',' ORDER BY a_target.attname) as target_cols
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 ck.conname, ck.target_schema, ck.target_table, ck.consrc)
SELECT target_cols, string_agg (target_schema || '.' || target_table || '.' || conname || '.(' || consrc || ')', ', ' ORDER BY target_schema, target_table, conname) AS tables
FROM ck_names
GROUP BY target_cols
HAVING Count(DISTINCT consrc)>1
AND Count(DISTINCT (target_schema || '.' || target_table))>1
ORDER BY target_cols;
Collections
This query belongs to the following collections:
Name
Description
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 .
Categories
This query is classified under the following categories:
Name
Description
CHECK constraints
Queries of this category provide information about CHECK constraints.
Comfortability of database evolution
Queries of this category provide information about the means that influence database evolution.
Inconsistencies
Queries of this catergory provide information about inconsistencies of solving the same problem in different places.