gojsj2025/backend/docs/gorm/Update.md

Update Save All Fields Save will save all fields when performing the Updating SQL

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; Save is an upsert function:

If the value contains no primary key, it performs Create If the value has a primary key, it first executes Update (all fields, by Select()). If rows affected = 0 after Update, it automatically falls back to Create. 💡 Note: Save guarantees either an update or insert will occur. To prevent unintended creation when no rows match, use Select().Updates() .

db.Save(&User{Name: "jinzhu", Age: 100}) // INSERT INTO users (name,age,birthday,update_at) VALUES ("jinzhu",100,"0000-00-00 00:00:00","0000-00-00 00:00:00")

db.Save(&User{ID: 1, Name: "jinzhu", Age: 100}) // UPDATE users SET name="jinzhu",age=100,birthday="0000-00-00 00:00:00",update_at="0000-00-00 00:00:00" WHERE id = 1 NOTE Don’t use Save with Model, it’s an Undefined Behavior.

Update single column When updating a single column with Update, it needs to have any conditions or it will raise error ErrMissingWhereClause, checkout Block Global Updates for details. When using the Model method and its value has a primary value, the primary key will be used to build the condition, for example:

// 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 supports updating with struct or map[string]interface{}, when updating with struct it will only update non-zero fields by default

// 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, "active": false}) // UPDATE users SET name='hello', age=18, active=false, updated_at='2013-11-17 21:34:10' WHERE id=111; NOTE When updating 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, "active": false}) // UPDATE users SET name='hello' WHERE id=111;

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

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

// Select all fields (select all fields include zero value fields) db.Model(&user).Select("*").Updates(User{Name: "jinzhu", Role: "admin", Age: 0})

// Select all fields but omit Role (select all fields include zero value fields) db.Model(&user).Select("*").Omit("Role").Updates(User{Name: "jinzhu", Role: "admin", Age: 0}) Update Hooks GORM allows the 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 a primary key value with Model, GORM will perform a batch update

// 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 updating a column with a 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 updating 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", Location: Location{X: 100, Y: 100}, }) // UPDATE user_with_points SET name="jinzhu",location=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; Returning Data From Modified Rows Returning changed data only works for databases which support Returning, for example:

// return all columns var users []User db.Model(&users).Clauses(clause.Returning{}).Where("role = ?", "admin").Update("salary", gorm.Expr("salary _ ?", 2)) // UPDATE users SET salary=salary _ 2,updated_at="2021-10-28 17:37:23.19" WHERE role = "admin" RETURNING * // users => []User{{ID: 1, Name: "jinzhu", Role: "admin", Salary: 100}, {ID: 2, Name: "jinzhu.2", Role: "admin", Salary: 1000}}

// return specified columns db.Model(&users).Clauses(clause.Returning{Columns: []clause.Column{{Name: "name"}, {Name: "salary"}}}).Where("role = ?", "admin").Update("salary", gorm.Expr("salary _ ?", 2)) // UPDATE users SET salary=salary _ 2,updated_at="2021-10-28 17:37:23.19" WHERE role = "admin" RETURNING name, salary // users => []User{{ID: 0, Name: "jinzhu", Role: "", Salary: 100}, {ID: 0, Name: "jinzhu.2", Role: "", Salary: 1000}} Check Field has changed? GORM provides the Changed method which could be used in Before Update Hooks, it will return whether the field has 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. It 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 update 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") { user.Age += 20 tx.Statement.SetColumn("Age", user.Age) } }

db.Model(&user).Update("Name", "jinzhu") GitHub tag (latest SemVer)