Name       string
	Constraint string // length(phone) >= 10
	*Field
}

func (chk *CheckConstraint) GetName() string { return chk.Name }

func (chk *CheckConstraint) Build() (sql string, vars []interface{}) {
	return "CONSTRAINT ? CHECK (?)", []interface{}{clause.Column{Name: chk.Name}, clause.Expr{SQL: chk.Constraint}}
}

// ParseCheckConstraints parse schema check constraints

	results := map[string]schema.CheckConstraint{
		"name_checker": {
			Name:       "name_checker",
			Constraint: "name <> 'jinzhu'",
		},
		"chk_user_checks_name2": {
			Name:       "chk_user_checks_name2",
			Constraint: "name <> 'jinzhu'",
		},
		"chk_user_checks_name3": {
			Name:       "chk_user_checks_name3",
			Constraint: "name <> 'jinzhu'",
		},
	}

	checks := user.ParseCheckConstraints()

	// ErrDuplicatedKey occurs when there is a unique key constraint violation
	ErrDuplicatedKey = errors.New("duplicated key not allowed")
	// ErrForeignKeyViolated occurs when there is a foreign key constraint violation
	ErrForeignKeyViolated = errors.New("violates foreign key constraint")
	// ErrCheckConstraintViolated occurs when there is a check constraint violation
	ErrCheckConstraintViolated = errors.New("violates check constraint")

type Language struct {
	Code string `gorm:"primarykey"`
	Name string
}

type Coupon struct {
	ID               int              `gorm:"primarykey; size:255"`
	AppliesToProduct []*CouponProduct `gorm:"foreignKey:CouponId;constraint:OnDelete:CASCADE"`
	AmountOff        uint32           `gorm:"column:amount_off"`
	PercentOff       float32          `gorm:"column:percent_off"`
}

type CouponProduct struct {

}

// IndexName generate index name
func (ns NamingStrategy) IndexName(table, column string) string {
	return ns.formatName("idx", table, ns.toDBName(column))
}

// UniqueName generate unique constraint name
func (ns NamingStrategy) UniqueName(table, column string) string {
	return ns.formatName("uni", table, ns.toDBName(column))
}

func (ns NamingStrategy) formatName(prefix, table, name string) string {

package schema

import (
	"gorm.io/gorm/clause"
)

// ConstraintInterface database constraint interface
type ConstraintInterface interface {
	GetName() string
	Build() (sql string, vars []interface{})
}

// GormDataTypeInterface gorm data type interface
type GormDataTypeInterface interface {
	GormDataType() string
}

// FieldNewValuePool field new scan value pool
type FieldNewValuePool interface {
	Get() interface{}

		gorm.Model
		SomeID  string
		OtherID string
		Data    string
	}

	DB.Migrator().DropTable(&Thing{})
	DB.Migrator().CreateTable(&Thing{})
	if err := DB.Exec("ALTER TABLE things ADD CONSTRAINT some_id_other_id_unique UNIQUE (some_id, other_id)").Error; err != nil {
		t.Error(err)
	}

	thing := Thing{
		SomeID:  "1234",
		OtherID: "1234",
		Data:    "something",
	}

	DB.Create(&thing)

	DropColumn(dst interface{}, field string) error
	AlterColumn(dst interface{}, field string) error
	MigrateColumn(dst interface{}, field *schema.Field, columnType ColumnType) error
	// MigrateColumnUnique migrate column's UNIQUE constraint, it's part of MigrateColumn.
	MigrateColumnUnique(dst interface{}, field *schema.Field, columnType ColumnType) error
	HasColumn(dst interface{}, field string) bool
	RenameColumn(dst interface{}, oldName, field string) error

	type City struct {
		gorm.Model
		Name string `gorm:"unique"`
	}

	type Museum struct {
		gorm.Model
		Name   string `gorm:"unique"`
		CityID uint
		City   City `gorm:"Constraint:OnUpdate:CASCADE,OnDelete:CASCADE;FOREIGNKEY:CityID;References:ID"`
	}

	db, err := OpenTestConnection(&gorm.Config{TranslateError: true})
	if err != nil {
		t.Fatalf("failed to connect database, got error %v", err)
	}

	Where        Where
	TargetWhere  Where
	OnConstraint string
	DoNothing    bool
	DoUpdates    Set
	UpdateAll    bool
}

func (OnConflict) Name() string {
	return "ON CONFLICT"
}

// Build build onConflict clause
func (onConflict OnConflict) Build(builder Builder) {
	if onConflict.OnConstraint != "" {
		builder.WriteString("ON CONSTRAINT ")
		builder.WriteString(onConflict.OnConstraint)
		builder.WriteByte(' ')
	} else {