Duplicate DEFAULT values of base table columns

Goal	Find base table columns that have both default value determined through a domain and default value that is directly attached to the column. Do not duplicate specifications of default values to avoid confusion and surprises. If column and domain both have a default value, then in case of inserting data the default value that is associated directly with the column is used.
Type	Problem detection (Each row in the result could represent a flaw in the design)
Reliability	High (Few or no false-positive results)
License	MIT (opens in new tab)
Fixing Suggestion	Drop either the default value of the domain or the default value that is directly associated with the column. If you drop the default value of the domain, then do not forget that the domain could be used in case of different columns.
Data Source	INFORMATION_SCHEMA only
SQL Query	SELECT c.table_schema, c.table_name, c.column_name, c.data_type, c.domain_schema, c.domain_name, c.column_default, domain_default FROM information_schema.columns AS c INNER JOIN information_schema.domains d USING (domain_schema, domain_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 AND domain_default IS NOT NULL ORDER BY c.table_schema, c.table_name, c.column_name;

SQL statements that help generate fixes for the identified problem.

Fix Action #1

WITH duplicate_defaults AS (SELECT c.table_schema, c.table_name, c.column_name,  c.data_type, c.domain_schema, c.domain_name, c.column_default, domain_default
FROM information_schema.columns AS c INNER JOIN information_schema.domains d USING (domain_schema, domain_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 
AND domain_default IS NOT NULL)
SELECT DISTINCT format('ALTER DOMAIN %1$I.%2$I DROP DEFAULT;', domain_schema, domain_name) AS statements
FROM duplicate_defaults 
ORDER BY statements;

Drop the domain default.

Fix Action #2

WITH duplicate_defaults AS (SELECT c.table_schema, c.table_name, c.column_name,  c.data_type, c.domain_schema, c.domain_name, c.column_default, domain_default
FROM information_schema.columns AS c INNER JOIN information_schema.domains d USING (domain_schema, domain_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 
AND domain_default IS NOT NULL)
SELECT DISTINCT format('ALTER TABLE %1$I.%2$I ALTER COLUMN %3$I DROP DEFAULT;', table_schema, table_name, column_name) AS statements
FROM duplicate_defaults 
ORDER BY statements;

Drop the column default.

SQL Query to Generate Fix Description

SQL Query to Generate Fix	Description
WITH duplicate_defaults AS (SELECT c.table_schema, c.table_name, c.column_name, c.data_type, c.domain_schema, c.domain_name, c.column_default, domain_default FROM information_schema.columns AS c INNER JOIN information_schema.domains d USING (domain_schema, domain_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 AND domain_default IS NOT NULL) SELECT DISTINCT format('ALTER DOMAIN %1$I.%2$I DROP DEFAULT;', domain_schema, domain_name) AS statements FROM duplicate_defaults ORDER BY statements;	Drop the domain default.
WITH duplicate_defaults AS (SELECT c.table_schema, c.table_name, c.column_name, c.data_type, c.domain_schema, c.domain_name, c.column_default, domain_default FROM information_schema.columns AS c INNER JOIN information_schema.domains d USING (domain_schema, domain_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 AND domain_default IS NOT NULL) SELECT DISTINCT format('ALTER TABLE %1$I.%2$I ALTER COLUMN %3$I DROP DEFAULT;', table_schema, table_name, column_name) AS statements FROM duplicate_defaults ORDER BY statements;	Drop the column default.

WITH duplicate_defaults AS (SELECT c.table_schema, c.table_name, c.column_name,  c.data_type, c.domain_schema, c.domain_name, c.column_default, domain_default
FROM information_schema.columns AS c INNER JOIN information_schema.domains d USING (domain_schema, domain_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 
AND domain_default IS NOT NULL)
SELECT DISTINCT format('ALTER DOMAIN %1$I.%2$I DROP DEFAULT;', domain_schema, domain_name) AS statements
FROM duplicate_defaults 
ORDER BY statements;

Drop the domain default.

WITH duplicate_defaults AS (SELECT c.table_schema, c.table_name, c.column_name,  c.data_type, c.domain_schema, c.domain_name, c.column_default, domain_default
FROM information_schema.columns AS c INNER JOIN information_schema.domains d USING (domain_schema, domain_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 
AND domain_default IS NOT NULL)
SELECT DISTINCT format('ALTER TABLE %1$I.%2$I ALTER COLUMN %3$I DROP DEFAULT;', table_schema, table_name, column_name) AS statements
FROM duplicate_defaults 
ORDER BY statements;

Drop the column default.

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 .

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:

Comfortability of database evolution

Queries of this category provide information about the means that influence database evolution.

Comfortability of data management

Queries of this category provide information about the means that have been used to make the use or management of database more comfortable and thus, more efficient.

Default value

Queries of this catergory provide information about the use of default values.

Domains

Queries of this category provide information about reusable specifications of column properties.

Duplication of implementation elements

Queries of this catergory provide information about the duplication of the database objects.

Name	Description
Comfortability of database evolution	Queries of this category provide information about the means that influence database evolution.
Comfortability of data management	Queries of this category provide information about the means that have been used to make the use or management of database more comfortable and thus, more efficient.
Default value	Queries of this catergory provide information about the use of default values.
Domains	Queries of this category provide information about reusable specifications of column properties.
Duplication of implementation elements	Queries of this catergory provide information about the duplication of the database objects.

Reference
https://en.wikipedia.org/wiki/Duplicate_code
The corresponding code smell in case of cleaning code is "G5: Duplication". (Robert C. Martin, Clean Code)