user := User{
  Name:            "jinzhu",
  BillingAddress:  Address{Address1: "Billing Address - Address 1"},
  ShippingAddress: Address{Address1: "Shipping Address - Address 1"},
  Emails:          []Email{
    {Email: "jinzhu@example.com"},
    {Email: "jinzhu-2@example.com"},
  },
  Languages:       []Language{
    {Name: "ZH"},
    {Name: "EN"},
  },
}

db.Create(&user)
//// BEGIN TRANSACTION;
//// INSERT INTO "addresses" (address1) VALUES ("Billing Address - Address 1");
//// INSERT INTO "addresses" (address1) VALUES ("Shipping Address - Address 1");
//// INSERT INTO "users" (name,billing_address_id,shipping_address_id) VALUES ("jinzhu", 1, 2);
//// INSERT INTO "emails" (user_id,email) VALUES (111, "jinzhu@example.com");
//// INSERT INTO "emails" (user_id,email) VALUES (111, "jinzhu-2@example.com");
//// INSERT INTO "languages" ("name") VALUES ('ZH');
//// INSERT INTO user_languages ("user_id","language_id") VALUES (111, 1);
//// INSERT INTO "languages" ("name") VALUES ('EN');
//// INSERT INTO user_languages ("user_id","language_id") VALUES (111, 2);
//// COMMIT;

db.Save(&user)

// 主キーがあっても関連を更新しませんが、参照は保存します
db.Set("gorm:association_autoupdate", false).Create(&user)
db.Set("gorm:association_autoupdate", false).Save(&user)

type User struct {
  gorm.Model
  Name       string
  CompanyID  uint
  // Don't update associations having primary key, but will save reference
  Company    Company `gorm:"association_autoupdate:false"`
}

// 主キーがあっても関連を更新しませんが、参照は保存します
db.Set("gorm:association_autoupdate", false).Create(&user)
db.Set("gorm:association_autoupdate", false).Save(&user)

db.Set("gorm:association_autoupdate", false).Set("gorm:association_autocreate", false).Create(&user)

type User struct {
  gorm.Model
  Name    string
  Company Company `gorm:"association_autoupdate:false;association_autocreate:false"`
}

db.Set("gorm:association_save_reference", false).Save(&user)
db.Set("gorm:association_save_reference", false).Create(&user)

type User struct {
  gorm.Model
  Name       string
  CompanyID  uint
  Company    Company `gorm:"association_save_reference:false"`
}

// Associationモードを開始します
var user User 
db.Model(&user).Association("Languages")
// `user` は、ソースであり、主キーを持っている必要があります。 
// `Languages` は、リレーションのためのソースのフィールド名です。 
// Associationモードは、この2つの条件が満たされた時に動作します。
// これをチェックするためにはこのように書きます。
db.Model(&user).Association("Languages").Error

db.Model(&user).Association("Languages").Find(&languages)

db.Model(&user).Association("Languages").Append([]Language{languageZH, languageEN})
db.Model(&user).Association("Languages").Append(Language{Name: "DE"})

db.Model(&user).Association("Languages").Replace([]Language{languageZH, languageEN})
db.Model(&user).Association("Languages").Replace(Language{Name: "DE"}, languageEN)

db.Model(&user).Association("Languages").Delete([]Language{languageZH, languageEN})
db.Model(&user).Association("Languages").Delete(languageZH, languageEN)

db.Model(&user).Association("Languages").Clear()

db.Model(&user).Association("Languages").Count()