func checkSchemaRelation(t *testing.T, s *schema.Schema, relation Relation) {
	t.Run("CheckRelation/"+relation.Name, func(t *testing.T) {
		if r, ok := s.Relationships.Relations[relation.Name]; ok {
			if r.Name != relation.Name {
				t.Errorf("schema %v relation name expects %v, but got %v", s, r.Name, relation.Name)
			}

			if r.Type != relation.Type {
				t.Errorf("schema %v relation name expects %v, but got %v", s, r.Type, relation.Type)

	db.Stmts[query] = &cacheStmt
	db.Mux.Unlock()

	// prepare completed
	defer close(cacheStmt.prepared)

	// Reason why cannot lock conn.PrepareContext
	// suppose the maxopen is 1, g1 is creating record and g2 is querying record.
	// 1. g1 begin tx, g1 is requeue because of waiting for the system call, now `db.ConnPool` db.numOpen == 1.