约束

少于1分钟

原文：https://gorm.io/docs/constraints.html

GORM allows create database constraints with tag, constraints will be created when AutoMigrate or CreateTable with GORM

GORM 允许使用标签创建数据库约束，当执行 AutoMigrate 或 CreateTable 与 GORM 时，将创建这些约束。

CHECK Constraint

Create CHECK constraints with tag check

使用 check 标签创建 CHECK 约束：

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type UserIndex struct {
  Name  string `gorm:"check:name_checker,name <> 'jinzhu'"`
  Name2 string `gorm:"check:name <> 'jinzhu'"`
  Name3 string `gorm:"check:,name <> 'jinzhu'"`
}

Index Constraint

Checkout Database Indexes

查看数据库索引。

Foreign Key Constraint

GORM will creates foreign keys constraints for associations, you can disable this feature during initialization:

GORM 将为关联关系创建外键约束，您可以在初始化过程中禁用此功能：

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db, err := gorm.Open(sqlite.Open("gorm.db"), &gorm.Config{
  DisableForeignKeyConstraintWhenMigrating: true,
})

GORM allows you setup FOREIGN KEY constraints’s OnDelete, OnUpdate option with tag constraint, for example:

GORM 允许您使用 constraint 标签的 OnDelete、OnUpdate 选项设置 FOREIGN KEY 约束，例如：

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type User struct {
  gorm.Model
  CompanyID  int
  Company    Company    `gorm:"constraint:OnUpdate:CASCADE,OnDelete:SET NULL;"`
  CreditCard CreditCard `gorm:"constraint:OnUpdate:CASCADE,OnDelete:SET NULL;"`
}

type CreditCard struct {
  gorm.Model
  Number string
  UserID uint
}

type Company struct {
  ID   int
  Name string
}

最后修改 October 10, 2024: 更新 (a4b8f85)