Update

Save All Fields

Saveは 、SQLを実行するときにすべてのフィールドを更新します。

db.First(&user)

user.Name = "jinzhu 2"
user.Age = 100
db.Save(&user)
// UPDATE users SET name='jinzhu 2', age=100, birthday='2016-01-01', updated_at = '2013-11-17 21:34:10' WHERE id=111;

Update single column

Updateメソッドで単一のカラムを更新する際には、何らかの条件を持っていないと、ErrMissingWhereClauseエラーが発生します。詳細については、Block Global Updates をチェックしてください。Modelメソッドを使用し、その実体が主キーに値するフィールドを持つ場合、条件として実体が持つ主キーが指定されます。

// Update with conditions
db.Model(&User{}).Where("active = ?", true).Update("name", "hello")
// UPDATE users SET name='hello', updated_at='2013-11-17 21:34:10' WHERE active=true;

// User's ID is `111`:
db.Model(&user).Update("name", "hello")
// UPDATE users SET name='hello', updated_at='2013-11-17 21:34:10' WHERE id=111;

// Update with conditions and model value
db.Model(&user).Where("active = ?", true).Update("name", "hello")
// UPDATE users SET name='hello', updated_at='2013-11-17 21:34:10' WHERE id=111 AND active=true;

Updates multiple columns

Updates構造体もしくはmap[string]interface{}での更新に対応しています。構造体での更新時のみ、非ゼロ値のフィールドはデフォルト値が設定されます

// Update attributes with `struct`, will only update non-zero fields
db.Model(&user).Updates(User{Name: "hello", Age: 18, Active: false})
// UPDATE users SET name='hello', age=18, updated_at = '2013-11-17 21:34:10' WHERE id = 111;

// Update attributes with `map`
db.Model(&user).Updates(map[string]interface{}{"name": "hello", "age": 18, "actived": false})
// UPDATE users SET name='hello', age=18, actived=false, updated_at='2013-11-17 21:34:10' WHERE id=111;

NOTE When update with struct, GORM will only update non-zero fields, you might want to use map to update attributes or use Select to specify fields to update

Update Selected Fields

If you want to update selected fields or ignore some fields when updating, you can use Select, Omit

// Select with Map
// User's ID is `111`:
db.Model(&user).Select("name").Updates(map[string]interface{}{"name": "hello", "age": 18, "actived": false})
// UPDATE users SET name='hello' WHERE id=111;

db.Model(&user).Omit("name").Updates(map[string]interface{}{"name": "hello", "age": 18, "actived": false})
// UPDATE users SET age=18, actived=false, updated_at='2013-11-17 21:34:10' WHERE id=111;

// Select with Struct (select zero value fields)
db.Model(&result).Select("Name", "Age").Updates(User{Name: "new_name", Age: 0})
// UPDATE users SET name='new_name', age=0 WHERE id=111;

Update Hooks

GORM allows hooks BeforeSave, BeforeUpdate, AfterSave, AfterUpdate, those methods will be called when updating a record, refer Hooks for details

func (u *User) BeforeUpdate(tx *gorm.DB) (err error) {
if u.Role == "admin" {
return errors.New("admin user not allowed to update")
}
return
}

Batch Updates

If we haven’t specified a record having primary key value with Model, GORM will perform a batch updates

// Update with struct
db.Model(User{}).Where("role = ?", "admin").Updates(User{Name: "hello", Age: 18})
// UPDATE users SET name='hello', age=18 WHERE role = 'admin;

// Update with map
db.Table("users").Where("id IN ?", []int{10, 11}).Updates(map[string]interface{}{"name": "hello", "age": 18})
// UPDATE users SET name='hello', age=18 WHERE id IN (10, 11);

Block Global Updates

If you perform a batch update without any conditions, GORM WON’T run it and will return ErrMissingWhereClause error by default

You have to use some conditions or use raw SQL or enable the AllowGlobalUpdate mode, for example:

db.Model(&User{}).Update("name", "jinzhu").Error // gorm.ErrMissingWhereClause

db.Model(&User{}).Where("1 = 1").Update("name", "jinzhu")
// UPDATE users SET `name` = "jinzhu" WHERE 1=1

db.Exec("UPDATE users SET name = ?", "jinzhu")
// UPDATE users SET name = "jinzhu"

db.Session(&gorm.Session{AllowGlobalUpdate: true}).Model(&User{}).Update("name", "jinzhu")
// UPDATE users SET `name` = "jinzhu"

Updated Records Count

Get the number of rows affected by a update

// Get updated records count with `RowsAffected`
result := db.Model(User{}).Where("role = ?", "admin").Updates(User{Name: "hello", Age: 18})
// UPDATE users SET name='hello', age=18 WHERE role = 'admin;

result.RowsAffected // returns updated records count
result.Error // returns updating error

Advanced

Update with SQL Expression

GORM allows updates column with SQL expression, e.g:

// product's ID is `3`
db.Model(&product).Update("price", gorm.Expr("price * ? + ?", 2, 100))
// UPDATE "products" SET "price" = price * 2 + 100, "updated_at" = '2013-11-17 21:34:10' WHERE "id" = 3;

db.Model(&product).Updates(map[string]interface{}{"price": gorm.Expr("price * ? + ?", 2, 100)})
// UPDATE "products" SET "price" = price * 2 + 100, "updated_at" = '2013-11-17 21:34:10' WHERE "id" = 3;

db.Model(&product).UpdateColumn("quantity", gorm.Expr("quantity - ?", 1))
// UPDATE "products" SET "quantity" = quantity - 1 WHERE "id" = 3;

db.Model(&product).Where("quantity > 1").UpdateColumn("quantity", gorm.Expr("quantity - ?", 1))
// UPDATE "products" SET "quantity" = quantity - 1 WHERE "id" = 3 AND quantity > 1;

And GORM also allows update with SQL Expression/Context Valuer with Customized Data Types, e.g:

// Create from customized data type
type Location struct {
X, Y int
}

func (loc Location) GormValue(ctx context.Context, db *gorm.DB) clause.Expr {
return clause.Expr{
SQL: "ST_PointFromText(?)",
Vars: []interface{}{fmt.Sprintf("POINT(%d %d)", loc.X, loc.Y)},
}
}

db.Model(&User{ID: 1}).Updates(User{
Name: "jinzhu",
Point: Point{X: 100, Y: 100},
})
// UPDATE `user_with_points` SET `name`="jinzhu",`point`=ST_PointFromText("POINT(100 100)") WHERE `id` = 1

Update from SubQuery

Update a table by using SubQuery

db.Model(&user).Update("company_name", db.Model(&Company{}).Select("name").Where("companies.id = users.company_id"))
// UPDATE "users" SET "company_name" = (SELECT name FROM companies WHERE companies.id = users.company_id);

db.Table("users as u").Where("name = ?", "jinzhu").Update("company_name", db.Table("companies as c").Select("name").Where("c.id = u.company_id"))

db.Table("users as u").Where("name = ?", "jinzhu").Updates(map[string]interface{}{}{"company_name": db.Table("companies as c").Select("name").Where("c.id = u.company_id")})

Without Hooks/Time Tracking

If you want to skip Hooks methods and don’t track the update time when updating, you can use UpdateColumn, UpdateColumns, it works like Update, Updates

// Update single column
db.Model(&user).UpdateColumn("name", "hello")
// UPDATE users SET name='hello' WHERE id = 111;

// Update multiple columns
db.Model(&user).UpdateColumns(User{Name: "hello", Age: 18})
// UPDATE users SET name='hello', age=18 WHERE id = 111;

// Update selected columns
db.Model(&user).Select("name", "age").UpdateColumns(User{Name: "hello", Age: 0})
// UPDATE users SET name='hello', age=0 WHERE id = 111;

Check Field has changed?

GORM provides Changed method could be used in Before Update Hooks, it will return the field changed or not

The Changed method only works with methods Update, Updates, and it only checks if the updating value from Update / Updates equals the model value, will return true if it is changed and not omitted

func (u *User) BeforeUpdate(tx *gorm.DB) (err error) {
// if Role changed
if tx.Statement.Changed("Role") {
return errors.New("role not allowed to change")
}

if tx.Statement.Changed("Name", "Admin") { // if Name or Role changed
tx.Statement.SetColumn("Age", 18)
}

// if any fields changed
if tx.Statement.Changed() {
tx.Statement.SetColumn("RefreshedAt", time.Now())
}
return nil
}

db.Model(&User{ID: 1, Name: "jinzhu"}).Updates(map[string]interface{"name": "jinzhu2"})
// Changed("Name") => true
db.Model(&User{ID: 1, Name: "jinzhu"}).Updates(map[string]interface{"name": "jinzhu"})
// Changed("Name") => false, `Name` not changed
db.Model(&User{ID: 1, Name: "jinzhu"}).Select("Admin").Updates(map[string]interface{
"name": "jinzhu2", "admin": false,
})
// Changed("Name") => false, `Name` not selected to update

db.Model(&User{ID: 1, Name: "jinzhu"}).Updates(User{Name: "jinzhu2"})
// Changed("Name") => true
db.Model(&User{ID: 1, Name: "jinzhu"}).Updates(User{Name: "jinzhu"})
// Changed("Name") => false, `Name` not changed
db.Model(&User{ID: 1, Name: "jinzhu"}).Select("Admin").Updates(User{Name: "jinzhu2"})
// Changed("Name") => false, `Name` not selected to update

Change Updating Values

To change updating values in Before Hooks, you should use SetColumn unless it is a full updates with Save, for example:

func (user *User) BeforeSave(tx *gorm.DB) (err error) {
if pw, err := bcrypt.GenerateFromPassword(user.Password, 0); err == nil {
tx.Statement.SetColumn("EncryptedPassword", pw)
}

if tx.Statement.Changed("Code") {
s.Age += 20
tx.Statement.SetColumn("Age", s.Age+20)
}
}

db.Model(&user).Update("Name", "jinzhu")