Preconditions

• HeidiSQL version: 12.1.0.6540
• Database type and version: postgresql 14.4.0
• OS: Windows

Describe the bug

HeidiSQL is looking for constraints (e.g. foreign key) by examining the information_schema.constraint_column_usage table. Unfortunately, columns will only be returned if the user is the owner of the table. See: https://www.postgresql.org/docs/current/infoschema-constraint-column-usage.html So if I connect to the database as any other user, e.g. a read-only user, then this information is not being shown.

As an alternative, foreign keys can be discovered with a slightly different query:

SELECT 
  conrelid::regclass AS table_from,
  conname,
  pg_get_constraintdef(c.oid) AS constraintdef
FROM pg_constraint c 
JOIN pg_namespace n 
  ON n.oid = c.connamespace 
WHERE contype IN ('f') 
AND n.nspname = 'schema_name_here';

To Reproduce

1. Create a database, schema, and a table with a foreign key to another table
2. Create a user with read only privileges: grant usage on schema "your_schema_name" to "ro_user", grant select on all tables in schema "your_schema_name" to "ro_user";
3. Connect to the database as "ro_user" and try to view foreign keys on your table, you will see 0.
4. Connect to the database as a super user, you will see the foreign keys.

Screenshots or Crash reports