"Toy": {
					Name:        "Toy",
					Type:        schema.HasOne,
					Schema:      "User",
					FieldSchema: "Toy",
					Polymorphic: Polymorphic{ID: "OwnerID", Type: "OwnerType", Value: "users"},
					References: []Reference{
						{ForeignKey: "OwnerType", ForeignSchema: "Toy", PrimaryValue: "users"},
						{ForeignKey: "OwnerType", ForeignSchema: "Toy", PrimaryValue: "users"},
					},
				},

	DB.Model(&users).Association("Toys").Append(
		&Toy{Name: "toy-slice-append-1"},
		[]Toy{{Name: "toy-slice-append-2-1"}, {Name: "toy-slice-append-2-2"}},
		&Toy{Name: "toy-slice-append-3"},
	)

	AssertAssociationCount(t, users, "Toys", 10, "After Append")

	// Replace -> same as append
	DB.Model(&users).Association("Toys").Replace(
		[]*Toy{{Name: "toy-slice-replace-1-1"}, {Name: "toy-slice-replace-1-2"}},

		pets := []Pet{{
			Name: "PolymorphicHasOne-Slice-1",
			Toy:  Toy{Name: "Toy-PolymorphicHasOne-Slice-1"},
		}, {
			Name: "PolymorphicHasOne-Slice-2",
			Toy:  Toy{Name: "Toy-PolymorphicHasOne-Slice-2"},
		}, {
			Name: "PolymorphicHasOne-Slice-3",
			Toy:  Toy{Name: "Toy-PolymorphicHasOne-Slice-3"},
		}}

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

					Name: "nested-joins-manager-company-1",
				},
				NamedPet: &Pet{
					Name: "nested-joins-manager-namepet-1",
					Toy: Toy{
						Name: "nested-joins-manager-namepet-toy-1",
					},
				},
			},
			NamedPet: &Pet{Name: "nested-joins-namepet-1", Toy: Toy{Name: "nested-joins-namepet-toy-1"}},
		},
		{
			Name:     "nested-joins-2",

				},
				NamedPet: &Pet{
					Name: "generics-nested-joins-manager-namepet-1",
					Toy: Toy{
						Name: "generics-nested-joins-manager-namepet-toy-1",
					},
				},
			},
			NamedPet: &Pet{Name: "generics-nested-joins-namepet-1", Toy: Toy{Name: "generics-nested-joins-namepet-toy-1"}},
		},
		{
			Name:     "generics-nested-joins-2",

		}
	}
}

// User has many Toys, its `Polymorphic` is `Owner`, Pet has one Toy, its `Polymorphic` is `Owner`
//
//	type User struct {
//	  Toys []Toy `gorm:"polymorphic:Owner;"`
//	}
//	type Pet struct {
//	  Toy Toy `gorm:"polymorphic:Owner;"`
//	}
//	type Toy struct {
//	  OwnerID   int
//	  OwnerType string
//	}

	if err := DB.Create(user).Error; err != nil {
		t.Fatalf("failed to create user, got error %v", err)
	}

	if err := DB.Select(clause.Associations, "Pets.Toy").Delete(&user).Error; err != nil {
		t.Fatalf("failed to delete user, got error %v", err)
	}

		},
		{
			Name: "Toys", Type: schema.HasMany, Schema: "User", FieldSchema: "Toy",
			Polymorphic: Polymorphic{ID: "OwnerID", Type: "OwnerType", Value: "users"},
			References:  []Reference{{"ID", "User", "OwnerID", "Toy", "", true}, {"", "", "OwnerType", "Toy", "users", false}},
		},
		{
			Name: "Company", Type: schema.BelongsTo, Schema: "User", FieldSchema: "Company",

And an `APIRoute` subclass to use that custom request class.

### Create a custom `GzipRequest` class { #create-a-custom-gziprequest-class }

/// tip

This is a toy example to demonstrate how it works, if you need Gzip support, you can use the provided [`GzipMiddleware`](../advanced/middleware.md#gzipmiddleware){.internal-link target=_blank}.

///

	// Create a user with initial associations using real database
	user := User{Name: "TestClauseAssociationSetUpdateWithMultipleAssociations", Age: 25}
	user.Pets = []*Pet{{Name: "original-pet"}}
	user.Toys = []Toy{{Name: "original-toy"}}
	if err := DB.Create(&user).Error; err != nil {
		t.Fatalf("failed to create user with associations: %v", err)
	}

	// Verify initial state using real database queries