Goal This query identifies foreign key columns where the identifier exhibits a minimal textual deviation (exactly one character) from the referenced candidate key. This specific proximity often indicates a typographical error or a singular/plural inconsistency (e.g., user_id vs users_id). The query explicitly excludes self-referencing constraints, where name divergence is structurally mandatory. Harmonizing these names enables the use of the simplified SQL USING syntax for joins, replacing verbose ON clauses and improving query readability.
Notes The query finds the foreign keys where the Levenshtein distance between the primary table column name and child table column name is one. The query uses a function from the fuzzystrmatch extension.
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 Rename the key column of the primary table or the foreign key column of the child table.
Data Source system catalog only
SQL Query 
CREATE EXTENSION IF NOT EXISTS fuzzystrmatch;
with fk as (select 
o.conname,
(select nspname from pg_namespace where oid=f.relnamespace) as foreign_schema,
f.relname as foreign_table,
f.oid as foreign_table_oid,
unnest(o.confkey) AS foreign_col,
(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
from pg_constraint o inner join pg_class c on c.oid = o.conrelid
inner join pg_class f on f.oid = o.confrelid 
where o.contype = 'f'),
fk_columns as (
select fk.conname, fk.foreign_schema, fk.foreign_table, a_foreign.attname as foreign_col, fk.target_schema, fk.target_table, a_target.attname as target_col
from fk inner join pg_attribute a_foreign on fk.foreign_col = a_foreign.attnum and fk.foreign_table_oid = a_foreign.attrelid and a_foreign.attisdropped = false
inner join pg_attribute a_target on fk.target_col = a_target.attnum and fk.target_table_oid = a_target.attrelid and a_target.attisdropped = false)
select *
from fk_columns
where ((foreign_schema<>target_schema) or (foreign_schema=target_schema and foreign_table<>target_table)) and foreign_col<>target_col 
and levenshtein_less_equal(foreign_col,target_col,1)=1
order by target_schema, target_table, conname;

DROP EXTENSION IF EXISTS fuzzystrmatch;

Collections

This query belongs to the following collections:

Find problems about names

A selection of queries that return information about the names of database objects. Contains all the types of queries - problem detection, software measure, and general overview.

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 .

NameDescription
Find problems about namesA selection of queries that return information about the names of database objects. Contains all the types of queries - problem detection, software measure, and general overview.
Find problems automaticallyQueries, 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 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.

Naming

Queries of this category provide information about the style of naming.

Relationships between tables

Queries of this category provide information about how database tables are connected to each other and whether such connections have been explicitly defined and whether it has been done correctly.

NameDescription
Comfortability of data managementQueries 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.
NamingQueries of this category provide information about the style of naming.
Relationships between tablesQueries of this category provide information about how database tables are connected to each other and whether such connections have been explicitly defined and whether it has been done correctly.