CONTRIBUTING.md

Implementing a new check

Write a new SQL query

Each database structure check starts with an SQL query to the pg_catalog.

1. SQLFluff is used as a linter for all SQL queries
2. All queries must be schema-aware, i.e. we filter out database objects on a schema basis:

   where
       nsp.nspname = :schema_name_param::text

3. All tables and indexes names in the query results must be schema-qualified. We use ::regclass on oid for that.

   select
       psui.relid::regclass::text as table_name,
       psui.indexrelid::regclass::text as index_name

4. All names should be enclosed in double quotes, if required.
5. The columns for the index or foreign key must be returned in the order they are used in the index or foreign key:

   select
       array_agg(quote_ident(a.attname) || ',' || a.attnotnull::text order by u.ordinality) as columns

6. All query results must be ordered in some way.
7. All queries must have a brief description. Links to documentation or articles with detailed descriptions are welcome.
8. The name of the sql-file with a query must correspond to diagnostic name in Java project.
9. Remember to update README.md.