Find table CHECK constraints that involve two columns that have the same default value. However the constraint assumes that the values must be unequal or one value must be bigger than another.
Notes
The query considers both default values that are associated directly with a column as well as default values that are associated through a domain.
Type
Problem detection (Each row in the result could represent a flaw in the design)
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, 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
where (consrc~'(<|>|<>)' and consrc!~'(>=|<=)' and consrc!~*'not[[:space:]]*\(.*')
or (consrc~'(>=|<=)' and consrc~*'not[[:space:]]*\(.*')),
defaults AS (SELECT c.table_schema, t.table_type, c.table_name, c.column_name, coalesce(c.column_default, domain_default) AS default_value,
CASE WHEN c.column_default IS NOT NULL THEN 'Column default' ELSE 'Domain default' END AS default_type
FROM information_schema.columns AS c LEFT JOIN information_schema.domains d USING (domain_schema, domain_name)
INNER JOIN INFORMATION_SCHEMA.tables AS t USING (table_schema, table_name)
WHERE c.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)
AND (column_default IS NOT NULL OR domain_default IS NOT NULL))
SELECT conname, target_schema, target_table, string_agg(target_col, ', ' ORDER BY target_col) AS target_col, any_value(default_value), any_value(consrc) AS consrc
FROM ck_names INNER JOIN defaults
ON ck_names.target_schema=defaults.table_schema
AND ck_names.target_table=defaults.table_name
AND ck_names.target_col=defaults.column_name
GROUP BY conname, target_schema, target_table
HAVING Min(default_value)=Max(default_value)
AND Count(*)>1
ORDER BY target_schema, target_table, conname;
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.
Default value
Queries of this catergory provide information about the use of default values.