-- 022_job_post_requisition_unique.sql
-- 021 originally created a non-unique ix_job_posts_requisition_id. Replace it
-- with a unique index so the optional job_posts.requisition_id link is 1:1.
-- Postgres unique indexes allow multiple NULLs. Applied at startup by
-- alembic_setup.run_manual_sql(). Needed because prod boots with
-- DB_AUTOGENERATE=false.

DROP INDEX IF EXISTS app.ix_job_posts_requisition_id;

CREATE UNIQUE INDEX IF NOT EXISTS uq_job_posts_requisition_id
    ON app.job_posts (requisition_id);