t.Fatalf("errors happened when create: %v", err)
		}

		for _, pet := range pets {
			CheckPet(t, *pet, *pet)
		}
	})
}

func TestCreateEmptyStruct(t *testing.T) {
	type EmptyStruct struct {
		ID uint
	}
	DB.Migrator().DropTable(&EmptyStruct{})

	if err := DB.AutoMigrate(&EmptyStruct{}); err != nil {
		t.Errorf("no error should happen when auto migrate, but got %v", err)
	}

		if field == nil {
			continue
		}

		if len(joinFields) == 0 || len(joinFields[idx]) == 0 {
			db.AddError(field.Set(db.Statement.Context, reflectValue, values[idx]))
		} else { // joinFields count is larger than 2 when using join
			var isNilPtrValue bool
			var relValue reflect.Value
			// does not contain raw dbname
			nestedJoinSchemas := joinFields[idx][:len(joinFields[idx])-1]
			// current reflect value

	tx = db.getInstance()
	tx.Statement.Distinct = true
	if len(args) > 0 {
		tx = tx.Select(args[0], args[1:]...)
	}
	return
}

// Select specify fields that you want when querying, creating, updating
//
// Use Select when you only want a subset of the fields. By default, GORM will select all fields.
// Select accepts both string arguments and arrays.
//
//	// Select name and age of user using multiple arguments

			pkFieldName = db.Statement.Schema.PrioritizedPrimaryField.DBName
		}

		// append @id column with value for auto-increment primary key
		// the @id value is correct, when: 1. without setting auto-increment primary key, 2. database AutoIncrementIncrement = 1
		switch values := db.Statement.Dest.(type) {
		case map[string]interface{}:
			values[pkFieldName] = insertID

		Pets:      2,
		Toys:      3,
		Company:   true,
		Manager:   true,
		Team:      4,
		Languages: 3,
		Friends:   1,
	})

	if err := DB.Create(&user).Error; err != nil {
		t.Fatalf("errors happened when create: %v", err)
	}

	CheckUser(t, user, user)

	var user2 User
	DB.Preload(clause.Associations).Find(&user2, "id = ?", user.ID)
	CheckUser(t, user2, user)

	Serializer             SerializerInterface
	NewValuePool           FieldNewValuePool

	// In some db (e.g. MySQL), Unique and UniqueIndex are indistinguishable.
	// When a column has a (not Mul) UniqueIndex, Migrator always reports its gorm.ColumnType is Unique.
	// It causes field unnecessarily migration.