Domains are like words that can be used to construct generalized claims about the real world (table predicates). Better not to duplicate the words in the dictionary.
Notes
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)
Rename a domain. In case of duplication drop the duplicates and refactor the database so that the remaining domain will be used everywhere it is needed.
Data Source
INFORMATION_SCHEMA only
SQL Query
WITH domains AS (SELECT domain_schema, domain_name
FROM information_schema.domains
WHERE domain_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 domain_name, string_agg(domain_schema,'; ' ORDER BY domain_schema) AS schemas, Count(*) AS number_of_domains
FROM domains
GROUP BY domain_name
HAVING Count(*)>1
ORDER BY domain_name, Count(*) DESC;
SQL statements that help generate fixes for the identified problem.
SQL Query to Generate Fix
Description
WITH domains AS (SELECT domain_schema, domain_name
FROM information_schema.domains
WHERE domain_schema NOT IN (SELECT schema_name
FROM INFORMATION_SCHEMA.schemata
WHERE schema_name<>'public' AND
schema_owner='postgres' AND schema_name IS NOT NULL)),
duplicates AS (SELECT domain_name
FROM domains
GROUP BY domain_name
HAVING Count(*)>1)
SELECT format('DROP DOMAIN %1$I.%2$I;', domain_schema, domain_name) AS statements
FROM domains
WHERE domain_name IN (SELECT domain_name
FROM duplicates)
ORDER BY domain_schema, domain_name;
Drop the domain.
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
Comfortability of database evolution
Queries of this category provide information about the means that influence database evolution.
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.
Naming
Queries of this category provide information about the style of naming.