golang gorm数据预加载软删硬删
Jeff的技术栈 人气:01. orm读写数据
1. 创建
1.1. 创建记录
user := User{Name: "Jinzhu", Age: 18, Birthday: time.Now()} db.NewRecord(user) // => 主键为空返回`true` db.Create(&user) db.NewRecord(user) // => 创建`user`后返回`false`
1.2. 默认值
您可以在gorm tag中定义默认值,然后插入SQL将忽略具有默认值的这些字段,并且其值为空,并且在将记录插入数据库后,gorm将从数据库加载这些字段的值。
type Animal struct { ID int64 Name string `gorm:"default:'galeone'"` Age int64 } var animal = Animal{Age: 99, Name: ""} db.Create(&animal) // INSERT INTO animals("age") values('99'); // SELECT name from animals WHERE ID=111; // 返回主键为 111 // animal.Name => 'galeone'
1.3. 在Callbacks中设置主键
如果要在BeforeCreate回调中设置主字段的值,可以使用scope.SetColumn,例如:
func (user *User) BeforeCreate(scope *gorm.Scope) error { scope.SetColumn("ID", uuid.New()) return nil }
1.4. 扩展创建选项
// 为Instert语句添加扩展SQL选项 db.Set("gorm:insert_option", "ON CONFLICT").Create(&product) // INSERT INTO products (name, code) VALUES ("name", "code") ON CONFLICT;
2. 查询
// 获取第一条记录,按主键排序 db.First(&user) //// SELECT * FROM users ORDER BY id LIMIT 1; // 获取最后一条记录,按主键排序 db.Last(&user) //// SELECT * FROM users ORDER BY id DESC LIMIT 1; // 获取所有记录 db.Find(&users) //// SELECT * FROM users; // 使用主键获取记录 db.First(&user, 10) //// SELECT * FROM users WHERE id = 10;
2.1. Where查询条件 (简单SQL)
// 获取第一个匹配记录 db.Where("name = ?", "jinzhu").First(&user) //// SELECT * FROM users WHERE name = 'jinzhu' limit 1; // 获取所有匹配记录 db.Where("name = ?", "jinzhu").Find(&users) //// SELECT * FROM users WHERE name = 'jinzhu'; db.Where("name <> ?", "jinzhu").Find(&users) // IN db.Where("name in (?)", []string{"jinzhu", "jinzhu 2"}).Find(&users) // LIKE db.Where("name LIKE ?", "%jin%").Find(&users) // AND db.Where("name = ? AND age >= ?", "jinzhu", "22").Find(&users) // Time db.Where("updated_at > ?", lastWeek).Find(&users) db.Where("created_at BETWEEN ? AND ?", lastWeek, today).Find(&users)
2.2. Where查询条件 (Struct & Map)
注意:当使用struct查询时,GORM将只查询那些具有值的字段
// Struct db.Where(&User{Name: "jinzhu", Age: 20}).First(&user) //// SELECT * FROM users WHERE name = "jinzhu" AND age = 20 LIMIT 1; // Map db.Where(map[string]interface{}{"name": "jinzhu", "age": 20}).Find(&users) //// SELECT * FROM users WHERE name = "jinzhu" AND age = 20; // 主键的Slice db.Where([]int64{20, 21, 22}).Find(&users) //// SELECT * FROM users WHERE id IN (20, 21, 22);
2.3. Not条件查询
db.Not("name", "jinzhu").First(&user) //// SELECT * FROM users WHERE name <> "jinzhu" LIMIT 1; // Not In db.Not("name", []string{"jinzhu", "jinzhu 2"}).Find(&users) //// SELECT * FROM users WHERE name NOT IN ("jinzhu", "jinzhu 2"); // Not In slice of primary keys db.Not([]int64{1,2,3}).First(&user) //// SELECT * FROM users WHERE id NOT IN (1,2,3); db.Not([]int64{}).First(&user) //// SELECT * FROM users; // Plain SQL db.Not("name = ?", "jinzhu").First(&user) //// SELECT * FROM users WHERE NOT(name = "jinzhu"); // Struct db.Not(User{Name: "jinzhu"}).First(&user) //// SELECT * FROM users WHERE name <> "jinzhu";
2.4. 带内联条件的查询
注意:使用主键查询时,应仔细检查所传递的值是否为有效主键,以避免SQL注入
// 按主键获取 db.First(&user, 23) //// SELECT * FROM users WHERE id = 23 LIMIT 1; // 简单SQL db.Find(&user, "name = ?", "jinzhu") //// SELECT * FROM users WHERE name = "jinzhu"; db.Find(&users, "name <> ? AND age > ?", "jinzhu", 20) //// SELECT * FROM users WHERE name <> "jinzhu" AND age > 20; // Struct db.Find(&users, User{Age: 20}) //// SELECT * FROM users WHERE age = 20; // Map db.Find(&users, map[string]interface{}{"age": 20}) //// SELECT * FROM users WHERE age = 20;
2.5. Or条件查询
db.Where("role = ?", "admin").Or("role = ?", "super_admin").Find(&users) //// SELECT * FROM users WHERE role = 'admin' OR role = 'super_admin'; // Struct db.Where("name = 'jinzhu'").Or(User{Name: "jinzhu 2"}).Find(&users) //// SELECT * FROM users WHERE name = 'jinzhu' OR name = 'jinzhu 2'; // Map db.Where("name = 'jinzhu'").Or(map[string]interface{}{"name": "jinzhu 2"}).Find(&users)
2.6. 查询链
Gorm有一个可链接的API,你可以这样使用它
db.Where("name <> ?","jinzhu").Where("age >= ? and role <> ?",20,"admin").Find(&users) //// SELECT * FROM users WHERE name <> 'jinzhu' AND age >= 20 AND role <> 'admin'; db.Where("role = ?", "admin").Or("role = ?", "super_admin").Not("name = ?", "jinzhu").Find(&users)
2.7. 扩展查询选项
// 为Select语句添加扩展SQL选项 db.Set("gorm:query_option", "FOR UPDATE").First(&user, 10) //// SELECT * FROM users WHERE id = 10 FOR UPDATE;
2.8. FirstOrInit
获取第一个匹配的记录,或者使用给定的条件初始化一个新的记录(仅适用于struct,map条件)
// Unfound db.FirstOrInit(&user, User{Name: "non_existing"}) //// user -> User{Name: "non_existing"} // Found db.Where(User{Name: "Jinzhu"}).FirstOrInit(&user) //// user -> User{Id: 111, Name: "Jinzhu", Age: 20} db.FirstOrInit(&user, map[string]interface{}{"name": "jinzhu"}) //// user -> User{Id: 111, Name: "Jinzhu", Age: 20}
2.9. Attrs
如果未找到记录,则使用参数初始化结构
// Unfound db.Where(User{Name: "non_existing"}).Attrs(User{Age: 20}).FirstOrInit(&user) //// SELECT * FROM USERS WHERE name = 'non_existing'; //// user -> User{Name: "non_existing", Age: 20} db.Where(User{Name: "non_existing"}).Attrs("age", 20).FirstOrInit(&user) //// SELECT * FROM USERS WHERE name = 'non_existing'; //// user -> User{Name: "non_existing", Age: 20} // Found db.Where(User{Name: "Jinzhu"}).Attrs(User{Age: 30}).FirstOrInit(&user) //// SELECT * FROM USERS WHERE name = jinzhu'; //// user -> User{Id: 111, Name: "Jinzhu", Age: 20}
2.10. Assign
将参数分配给结果,不管它是否被找到
// Unfound db.Where(User{Name: "non_existing"}).Assign(User{Age: 20}).FirstOrInit(&user) //// user -> User{Name: "non_existing", Age: 20} // Found db.Where(User{Name: "Jinzhu"}).Assign(User{Age: 30}).FirstOrInit(&user) //// SELECT * FROM USERS WHERE name = jinzhu'; //// user -> User{Id: 111, Name: "Jinzhu", Age: 30}
2.11. FirstOrCreate
获取第一个匹配的记录,或创建一个具有给定条件的新记录(仅适用于struct, map条件)
// Unfound db.FirstOrCreate(&user, User{Name: "non_existing"}) //// INSERT INTO "users" (name) VALUES ("non_existing"); //// user -> User{Id: 112, Name: "non_existing"} // Found db.Where(User{Name: "Jinzhu"}).FirstOrCreate(&user) //// user -> User{Id: 111, Name: "Jinzhu"}
2.12. Attrs
如果未找到记录,则为参数分配结构
// Unfound db.Where(User{Name: "non_existing"}).Attrs(User{Age: 20}).FirstOrCreate(&user) //// SELECT * FROM users WHERE name = 'non_existing'; //// INSERT INTO "users" (name, age) VALUES ("non_existing", 20); //// user -> User{Id: 112, Name: "non_existing", Age: 20} // Found db.Where(User{Name: "jinzhu"}).Attrs(User{Age: 30}).FirstOrCreate(&user) //// SELECT * FROM users WHERE name = 'jinzhu'; //// user -> User{Id: 111, Name: "jinzhu", Age: 20}
2.13. Assign
将其分配给记录,而不管它是否被找到,并保存回数据库。
// Unfound db.Where(User{Name: "non_existing"}).Assign(User{Age: 20}).FirstOrCreate(&user) //// SELECT * FROM users WHERE name = 'non_existing'; //// INSERT INTO "users" (name, age) VALUES ("non_existing", 20); //// user -> User{Id: 112, Name: "non_existing", Age: 20} // Found db.Where(User{Name: "jinzhu"}).Assign(User{Age: 30}).FirstOrCreate(&user) //// SELECT * FROM users WHERE name = 'jinzhu'; //// UPDATE users SET age=30 WHERE id = 111; //// user -> User{Id: 111, Name: "jinzhu", Age: 30}
2.14. Select
指定要从数据库检索的字段,默认情况下,将选择所有字段;
db.Select("name, age").Find(&users) //// SELECT name, age FROM users; db.Select([]string{"name", "age"}).Find(&users) //// SELECT name, age FROM users; db.Table("users").Select("COALESCE(age,?)", 42).Rows() //// SELECT COALESCE(age,'42') FROM users;
2.15. Order
在从数据库检索记录时指定顺序,将重排序设置为true
以覆盖定义的条件
db.Order("age desc, name").Find(&users) //// SELECT * FROM users ORDER BY age desc, name; // Multiple orders db.Order("age desc").Order("name").Find(&users) //// SELECT * FROM users ORDER BY age desc, name; // ReOrder db.Order("age desc").Find(&users1).Order("age", true).Find(&users2) //// SELECT * FROM users ORDER BY age desc; (users1) //// SELECT * FROM users ORDER BY age; (users2)
2.16. Limit
指定要检索的记录数
db.Limit(3).Find(&users) //// SELECT * FROM users LIMIT 3; // Cancel limit condition with -1 db.Limit(10).Find(&users1).Limit(-1).Find(&users2) //// SELECT * FROM users LIMIT 10; (users1) //// SELECT * FROM users; (users2)
2.17. Offset
指定在开始返回记录之前要跳过的记录数
db.Offset(3).Find(&users) //// SELECT * FROM users OFFSET 3; // Cancel offset condition with -1 db.Offset(10).Find(&users1).Offset(-1).Find(&users2) //// SELECT * FROM users OFFSET 10; (users1) //// SELECT * FROM users; (users2)
eg:
type Info struct { Id int `json:"id"` Code string `json:"code"` HwCode string `json:"hw_code"` Name string `json:"name"` Des string `json:"des"` Created int64 `json:"created"` Updated int64 `json:"updated"` BrandId int `json:"brand_id"` } func (Info) TableName() string { return "bike_color" } func (o object) QueryInfo2(id int) *Info { r := new(Info) o.gDb.Where("id = ?",id).Find(&r) return r } // 列表 func (o object) QueryList2(page, PageSize int) (list []Info, total int) { o.gDb.Offset((page-1)*PageSize).Limit(PageSize).Find(&list) total = len(list) return }
2.18. Count
获取模型的记录数
db.Where("name = ?", "jinzhu").Or("name = ?", "jinzhu 2").Find(&users).Count(&count) //// SELECT * from USERS WHERE name = 'jinzhu' OR name = 'jinzhu 2'; (users) //// SELECT count(*) FROM users WHERE name = 'jinzhu' OR name = 'jinzhu 2'; (count) db.Model(&User{}).Where("name = ?", "jinzhu").Count(&count) //// SELECT count(*) FROM users WHERE name = 'jinzhu'; (count) db.Table("deleted_users").Count(&count) //// SELECT count(*) FROM deleted_users;
2.19. Group & Having
rows, err := db.Table("orders").Select("date(created_at) as date, sum(amount) as total").Group("date(created_at)").Rows() for rows.Next() { ... } rows, err := db.Table("orders").Select("date(created_at) as date, sum(amount) as total").Group("date(created_at)").Having("sum(amount) > ?", 100).Rows() for rows.Next() { ... } type Result struct { Date time.Time Total int64 } db.Table("orders").Select("date(created_at) as date, sum(amount) as total").Group("date(created_at)").Having("sum(amount) > ?", 100).Scan(&results)
2.20. Join
指定连接条件
rows, err := db.Table("users").Select("users.name, emails.email").Joins("left join emails on emails.user_id = users.id").Rows() for rows.Next() { ... } db.Table("users").Select("users.name, emails.email").Joins("left join emails on emails.user_id = users.id").Scan(&results) // 多个连接与参数 db.Joins("JOIN emails ON emails.user_id = users.id AND emails.email = ?", "jinzhu@example.org").Joins("JOIN credit_cards ON credit_cards.user_id = users.id").Where("credit_cards.number = ?", "411111111111").Find(&user)
2.21. Pluck
将模型中的单个列作为地图查询,如果要查询多个列,可以使用Scan
var ages []int64 db.Find(&users).Pluck("age", &ages) var names []string db.Model(&User{}).Pluck("name", &names) db.Table("deleted_users").Pluck("name", &names) // 要返回多个列,做这样: db.Select("name, age").Find(&users)
2.22. Scan
将结果扫描到另一个结构中。
type Result struct { Name string Age int } var result Result db.Table("users").Select("name, age").Where("name = ?", 3).Scan(&result) // Raw SQL db.Raw("SELECT name, age FROM users WHERE name = ?", 3).Scan(&result)
2.23. Scopes
将当前数据库连接传递到func(*DB) *DB
,可以用于动态添加条件
func AmountGreaterThan1000(db *gorm.DB) *gorm.DB { return db.Where("amount > ?", 1000) } func PaidWithCreditCard(db *gorm.DB) *gorm.DB { return db.Where("pay_mode_sign = ?", "C") } func PaidWithCod(db *gorm.DB) *gorm.DB { return db.Where("pay_mode_sign = ?", "C") } func OrderStatus(status []string) func (db *gorm.DB) *gorm.DB { return func (db *gorm.DB) *gorm.DB { return db.Scopes(AmountGreaterThan1000).Where("status in (?)", status) } } db.Scopes(AmountGreaterThan1000, PaidWithCreditCard).Find(&orders) // 查找所有信用卡订单和金额大于1000 db.Scopes(AmountGreaterThan1000, PaidWithCod).Find(&orders) // 查找所有COD订单和金额大于1000 db.Scopes(OrderStatus([]string{"paid", "shipped"})).Find(&orders) // 查找所有付费,发货订单
2.24. 指定表名
// 使用User结构定义创建`deleted_users`表 db.Table("deleted_users").CreateTable(&User{}) var deleted_users []User db.Table("deleted_users").Find(&deleted_users) //// SELECT * FROM deleted_users; db.Table("deleted_users").Where("name = ?", "jinzhu").Delete() //// DELETE FROM deleted_users WHERE name = 'jinzhu';
3. 预加载
db.Preload("Orders").Find(&users) //// SELECT * FROM users; //// SELECT * FROM orders WHERE user_id IN (1,2,3,4); db.Preload("Orders", "state NOT IN (?)", "cancelled").Find(&users) //// SELECT * FROM users; //// SELECT * FROM orders WHERE user_id IN (1,2,3,4) AND state NOT IN ('cancelled'); db.Where("state = ?", "active").Preload("Orders", "state NOT IN (?)", "cancelled").Find(&users) //// SELECT * FROM users WHERE state = 'active'; //// SELECT * FROM orders WHERE user_id IN (1,2) AND state NOT IN ('cancelled'); db.Preload("Orders").Preload("Profile").Preload("Role").Find(&users) //// SELECT * FROM users; //// SELECT * FROM orders WHERE user_id IN (1,2,3,4); // has many //// SELECT * FROM profiles WHERE user_id IN (1,2,3,4); // has one //// SELECT * FROM roles WHERE id IN (4,5,6); // belongs to
3.1. 自定义预加载SQL
您可以通过传递func(db *gorm.DB) *gorm.DB
(与Scopes的使用方法相同)来自定义预加载SQL,例如:
db.Preload("Orders", func(db *gorm.DB) *gorm.DB { return db.Order("orders.amount DESC") }).Find(&users) //// SELECT * FROM users; //// SELECT * FROM orders WHERE user_id IN (1,2,3,4) order by orders.amount DESC;
3.2. 嵌套预加载
db.Preload("Orders.OrderItems").Find(&users) db.Preload("Orders", "state = ?", "paid").Preload("Orders.OrderItems").Find(&users)
4. 更新
4.1. 更新全部字段
Save
将包括执行更新SQL时的所有字段,即使它没有更改
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;
4.2. 更新更改字段
如果只想更新更改的字段,可以使用Update
, Updates
// 更新单个属性(如果更改) db.Model(&user).Update("name", "hello") //// UPDATE users SET name='hello', updated_at='2013-11-17 21:34:10' WHERE id=111; // 使用组合条件更新单个属性 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; // 使用`map`更新多个属性,只会更新这些更改的字段 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; // 使用`struct`更新多个属性,只会更新这些更改的和非空白字段 db.Model(&user).Updates(User{Name: "hello", Age: 18}) //// UPDATE users SET name='hello', age=18, updated_at = '2013-11-17 21:34:10' WHERE id = 111; // 警告:当使用struct更新时,FORM将仅更新具有非空值的字段 // 对于下面的更新,什么都不会更新为"",0,false是其类型的空白值 db.Model(&user).Updates(User{Name: "", Age: 0, Actived: false})
4.3. 更新选择的字段
如果您只想在更新时更新或忽略某些字段,可以使用Select
, Omit
db.Model(&user).Select("name").Updates(map[string]interface{}{"name": "hello", "age": 18, "actived": false}) //// UPDATE users SET name='hello', updated_at='2013-11-17 21:34:10' 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;
4.4. 更新更改字段但不进行Callbacks
以上更新操作将执行模型的BeforeUpdate
, AfterUpdate
方法,更新其UpdatedAt
时间戳,在更新时保存它的Associations
,如果不想调用它们,可以使用UpdateColumn
, UpdateColumns
// 更新单个属性,类似于`Update` db.Model(&user).UpdateColumn("name", "hello") //// UPDATE users SET name='hello' WHERE id = 111; // 更新多个属性,与“更新”类似 db.Model(&user).UpdateColumns(User{Name: "hello", Age: 18}) //// UPDATE users SET name='hello', age=18 WHERE id = 111;
4.5. Batch Updates 批量更新
Callbacks
在批量更新时不会运行
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); // 使用struct更新仅适用于非零值,或使用map[string]interface{} db.Model(User{}).Updates(User{Name: "hello", Age: 18}) //// UPDATE users SET name='hello', age=18; // 使用`RowsAffected`获取更新记录计数 db.Model(User{}).Updates(User{Name: "hello", Age: 18}).RowsAffected
4.6. 使用SQL表达式更新
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" = '2'; 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" = '2'; DB.Model(&product).UpdateColumn("quantity", gorm.Expr("quantity - ?", 1)) //// UPDATE "products" SET "quantity" = quantity - 1 WHERE "id" = '2'; DB.Model(&product).Where("quantity > 1").UpdateColumn("quantity", gorm.Expr("quantity - ?", 1)) //// UPDATE "products" SET "quantity" = quantity - 1 WHERE "id" = '2' AND quantity > 1;
4.7. 在Callbacks中更改更新值
如果要使用BeforeUpdate
, BeforeSave
更改回调中的更新值,可以使用scope.SetColumn
,例如
func (user *User) BeforeSave(scope *gorm.Scope) (err error) { if pw, err := bcrypt.GenerateFromPassword(user.Password, 0); err == nil { scope.SetColumn("EncryptedPassword", pw) } }
4.8. 额外更新选项
// 为Update语句添加额外的SQL选项 db.Model(&user).Set("gorm:update_option", "OPTION (OPTIMIZE FOR UNKNOWN)").Update("name, "hello") //// UPDATE users SET name='hello', updated_at = '2013-11-17 21:34:10' WHERE id=111 OPTION (OPTIMIZE FOR UNKNOWN);
5. 删除/软删除
警告 删除记录时,需要确保其主要字段具有值,GORM将使用主键删除记录,如果主要字段为空,GORM将删除模型的所有记录
// 删除存在的记录 db.Delete(&email) //// DELETE from emails where id=10; // 为Delete语句添加额外的SQL选项 db.Set("gorm:delete_option", "OPTION (OPTIMIZE FOR UNKNOWN)").Delete(&email) //// DELETE from emails where id=10 OPTION (OPTIMIZE FOR UNKNOWN);
5.1. 批量删除
删除所有匹配记录
db.Where("email LIKE ?", "%jinzhu%").Delete(Email{}) //// DELETE from emails where email LIKE "%jinhu%"; db.Delete(Email{}, "email LIKE ?", "%jinzhu%") //// DELETE from emails where email LIKE "%jinhu%";
5.2. 软删除
如果模型有DeletedAt
字段,它将自动获得软删除功能! 那么在调用Delete
时不会从数据库中永久删除,而是只将字段DeletedAt
的值设置为当前时间。
db.Delete(&user) //// UPDATE users SET deleted_at="2013-10-29 10:23" WHERE id = 111; // 批量删除 db.Where("age = ?", 20).Delete(&User{}) //// UPDATE users SET deleted_at="2013-10-29 10:23" WHERE age = 20; // 软删除的记录将在查询时被忽略 db.Where("age = 20").Find(&user) //// SELECT * FROM users WHERE age = 20 AND deleted_at IS NULL; // 使用Unscoped查找软删除的记录 db.Unscoped().Where("age = 20").Find(&users) //// SELECT * FROM users WHERE age = 20; // 使用Unscoped永久删除记录 db.Unscoped().Delete(&order) //// DELETE FROM orders WHERE id=10;
6. 关联
默认情况下,当创建/更新记录时,GORM将保存其关联,如果关联具有主键,GORM将调用Update来保存它,否则将被创建。
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@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)
6.1. 创建/更新时跳过保存关联
默认情况下保存记录时,GORM也会保存它的关联,你可以通过设置gorm:save_associations
为false
跳过它。
db.Set("gorm:save_associations", false).Create(&user) db.Set("gorm:save_associations", false).Save(&user)
6.2. tag设置跳过保存关联
您可以使用tag来配置您的struct,以便在创建/更新时不会保存关联
type User struct { gorm.Model Name string CompanyID uint Company Company `gorm:"save_associations:false"` } type Company struct { gorm.Model Name string }
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