1 files changed, 54 insertions, 0 deletions
diff --git a/db/migrate/20221122210711_add_columns_to_postgres_foreign_keys.rb b/db/migrate/20221122210711_add_columns_to_postgres_foreign_keys.rb
new file mode 100644
index 00000000000..bef05e52a3a
--- /dev/null
+++ b/db/migrate/20221122210711_add_columns_to_postgres_foreign_keys.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+class AddColumnsToPostgresForeignKeys < Gitlab::Database::Migration[2.0]
+  def up
+    execute(<<~SQL)
+      CREATE OR REPLACE VIEW postgres_foreign_keys AS
+      SELECT
+          pg_constraint.oid AS oid,
+          pg_constraint.conname AS name,
+          constrained_namespace.nspname::text || '.'::text || constrained_table.relname::text AS constrained_table_identifier,
+          referenced_namespace.nspname::text || '.'::text || referenced_table.relname::text AS referenced_table_identifier,
+          constrained_table.relname::text AS constrained_table_name,
+          referenced_table.relname::text AS referenced_table_name,
+          constrained_cols.constrained_columns,
+          referenced_cols.referenced_columns,
+          pg_constraint.confdeltype AS on_delete_action,
+          pg_constraint.coninhcount > 0 as is_inherited
+      FROM pg_constraint
+               INNER JOIN pg_class constrained_table ON constrained_table.oid = pg_constraint.conrelid
+               INNER JOIN pg_class referenced_table ON referenced_table.oid = pg_constraint.confrelid
+               INNER JOIN pg_namespace constrained_namespace ON constrained_table.relnamespace = constrained_namespace.oid
+               INNER JOIN pg_namespace referenced_namespace ON referenced_table.relnamespace = referenced_namespace.oid
+               CROSS JOIN LATERAL (
+                  SELECT array_agg(pg_attribute.attname ORDER BY conkey.idx) -- must order here so that attributes are in correct order in array
+                  FROM unnest(pg_constraint.conkey) WITH ORDINALITY conkey(attnum, idx)
+                  INNER JOIN pg_attribute ON pg_attribute.attnum = conkey.attnum AND pg_attribute.attrelid = constrained_table.oid
+               ) constrained_cols(constrained_columns)
+              CROSS JOIN LATERAL (
+                  SELECT array_agg(pg_attribute.attname ORDER BY confkey.idx)
+                  FROM unnest(pg_constraint.confkey) WITH ORDINALITY confkey(attnum, idx)
+                  INNER JOIN pg_attribute ON pg_attribute.attnum = confkey.attnum AND pg_attribute.attrelid = referenced_table.oid
+              ) referenced_cols(referenced_columns)
+      WHERE contype = 'f';
+    SQL
+  end
+
+  def down
+    execute(<<~SQL)
+      DROP VIEW IF EXISTS postgres_foreign_keys;
+      CREATE OR REPLACE VIEW postgres_foreign_keys AS
+      SELECT
+          pg_constraint.oid AS oid,
+          pg_constraint.conname AS name,
+          constrained_namespace.nspname::text || '.'::text || constrained_table.relname::text AS constrained_table_identifier,
+          referenced_namespace.nspname::text || '.'::text || referenced_table.relname::text AS referenced_table_identifier
+      FROM pg_constraint
+               INNER JOIN pg_class constrained_table ON constrained_table.oid = pg_constraint.conrelid
+               INNER JOIN pg_class referenced_table ON referenced_table.oid = pg_constraint.confrelid
+               INNER JOIN pg_namespace constrained_namespace ON constrained_table.relnamespace = constrained_namespace.oid
+               INNER JOIN pg_namespace referenced_namespace ON referenced_table.relnamespace = referenced_namespace.oid
+      WHERE contype = 'f';
+    SQL
+  end
+end