Find foreign keys where the name of the foreign key column and the corresponding primary key/unique column is different and the difference is between two and four characters. Exclude foreign key columns that refer to the key of the same table because within each named table column names must be different. Simplify writing queries that have to join data from multiple base tables. If the columns that participate in the join condition have the same name, then one can use the USING syntax.
Notes
The query excludes relationships where the primary table key column has the name "id", "code", or "kood".
Type
Problem detection (Each row in the result could represent a flaw in the design)
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 foreign_col NOT IN ('id','code','kood')
and levenshtein(foreign_col,target_col) BETWEEN 2 AND 4
order by target_schema, target_table, conname;
DROP EXTENSION IF EXISTS fuzzystrmatch;
Collections
This query belongs to the following collections:
Name
Description
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.
Categories
This query is classified under the following categories:
Name
Description
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.