This query identifies potential redundancy or ambiguity in the schema by detecting pairs of user-defined domain names with high textual similarity. It utilizes the Levenshtein distance algorithm to find name pairs that differ by fewer than two characters. Crucially, the query implements a filter to exclude pairs where the divergence is attributable solely to numerical digits. This heuristic prevents false positives for valid domain variations based on size or version (e.g., d_name_20 vs. d_name_50), focusing the analysis strictly on likely typographical errors or semantic duplicates.
Notes
The query uses a function from the fuzzystrmatch extension.
Type
Problem detection (Each row in the result could represent a flaw in the design)
Make sure that the names are correct and there are no duplication or unused domains.
Data Source
INFORMATION_SCHEMA only
SQL Query
CREATE EXTENSION IF NOT EXISTS fuzzystrmatch;
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 d1.domain_schema AS domain1_schema, d1.domain_name AS domain1_name,
d2.domain_schema AS domain2_schema, d2.domain_name AS domain2_name
FROM domains AS d1, domains AS d2
WHERE NOT (d1.domain_schema=d2.domain_schema AND d1.domain_name=d2.domain_name)
AND translate(d1.domain_name,'0123456789','')<>translate(d2.domain_name,'0123456789','')
AND levenshtein(d1.domain_name,d2.domain_name)<=1
ORDER BY domain1_name, domain2_name;
DROP EXTENSION IF EXISTS fuzzystrmatch;
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
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.
Unused implementation elements
Queries of this catergory provide information about the database objects that are not used.