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()

		currentDatabase := m.DB.Migrator().CurrentDatabase()
		constraint, table := m.GuessConstraintInterfaceAndTable(stmt, name)
		if constraint != nil {
			name = constraint.GetName()
		}

		return m.DB.Raw(
			"SELECT count(*) FROM INFORMATION_SCHEMA.table_constraints WHERE constraint_schema = ? AND table_name = ? AND constraint_name = ?",
			currentDatabase, table, name,
		).Row().Scan(&count)
	})

	}

	expectedConstraintName := "fk_my_schema_a_very_very_very_very_very_very_very_very_l4db13eec"
	constraint := s.Relationships.Relations["Author"].ParseConstraint()

	if constraint.Name != expectedConstraintName {
		t.Fatalf(
			"expected constraint name %s, got %s",
			expectedConstraintName,
			constraint.Name,
		)
	}

	// 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")

			t.Fatalf("failed to parse user unique, got error %v", err)
		}

		constraints := user.ParseUniqueConstraints()
		if len(constraints) != 1 {
			t.Fatalf("failed to find unique constraint, got %v", constraints)
		}

		for key := range constraints {
			if len(key) != 63 {
				t.Errorf("failed to find unique constraint, got %v", constraints)
			}
		}
	})

	t.Run("naming strategy", func(t *testing.T) {

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)