gorm.Model
	UserID sql.NullInt64
	Number string
}

type Pet struct {
	gorm.Model
	UserID *uint
	Name   string
	Toy    Toy `gorm:"polymorphic:Owner;"`
}

type Toy struct {
	gorm.Model
	Name      string
	OwnerID   string
	OwnerType string
}

type Tools struct {
	gorm.Model
	Name     string
	CustomID string
	Type     string
}

type Company struct {
	ID   int

	type callback struct {
		name    string
		before  string
		after   string
		remove  bool
		replace bool
		err     string
		match   func(*gorm.DB) bool
		h       func(*gorm.DB)
	}

	datas := []struct {
		callbacks []callback
		err       string
		results   []string
	}{
		{
			callbacks: []callback{{h: c1}, {h: c2}, {h: c3}, {h: c4}, {h: c5}},
			results:   []string{"c1", "c2", "c3", "c4", "c5"},
		},
		{

		}
	})
}

type Relation struct {
	Name        string
	Type        schema.RelationshipType
	Schema      string
	FieldSchema string
	Polymorphic Polymorphic
	JoinTable   JoinTable
	References  []Reference
}

type Polymorphic struct {
	ID    string
	Type  string
	Value string
}

type JoinTable struct {
	Name   string
	Table  string
	Fields []schema.Field
}

type Index struct {
	TableName       string
	NameValue       string
	ColumnList      []string
	PrimaryKeyValue sql.NullBool
	UniqueValue     sql.NullBool
	OptionValue     string
}

// Table return the table name of the index.
func (idx Index) Table() string {
	return idx.TableName
}

// Name return the name of the index.
func (idx Index) Name() string {
	return idx.NameValue
}

	default:
		return false
	}
}

// ExplainSQL generate SQL string with given parameters, the generated SQL is expected to be used in logger, execute it might introduce a SQL injection vulnerability
func ExplainSQL(sql string, numericPlaceholder *regexp.Regexp, escaper string, avars ...interface{}) string {
	var (
		convertParams func(interface{}, int)
		vars          = make([]string, len(avars))
	)

	convertParams = func(v interface{}, idx int) {

	}

	var names []string
	DB.Table("users").Where("name like ?", "distinct%").Order("name").Pluck("name", &names)
	AssertEqual(t, names, []string{"distinct", "distinct", "distinct", "distinct-2", "distinct-3"})

	var names1 []string
	DB.Model(&User{}).Where("name like ?", "distinct%").Distinct().Order("name").Pluck("Name", &names1)

	AssertEqual(t, names1, []string{"distinct", "distinct-2", "distinct-3"})

	Test   func(ctx context.Context, begin time.Time, fc func() (sql string, rowsAffected int64), err error)
}

func (S Tracer) LogMode(level logger.LogLevel) logger.Interface {
	return S.Logger.LogMode(level)
}

func (S Tracer) Info(ctx context.Context, s string, i ...interface{}) {
	S.Logger.Info(ctx, s, i...)
}

func (S Tracer) Warn(ctx context.Context, s string, i ...interface{}) {
	S.Logger.Warn(ctx, s, i...)
}

		}
	}
}

// NamedExpr raw expression for named expr
type NamedExpr struct {
	SQL  string
	Vars []interface{}
}

// Build build raw expression
func (expr NamedExpr) Build(builder Builder) {
	var (
		idx              int
		inName           bool
		afterParenthesis bool
		namedMap         = make(map[string]interface{}, len(expr.Vars))
	)

	for _, v := range expr.Vars {
		switch value := v.(type) {

func (set Set) MergeClause(clause *Clause) {
	copiedAssignments := make([]Assignment, len(set))
	copy(copiedAssignments, set)
	clause.Expression = Set(copiedAssignments)
}

func Assignments(values map[string]interface{}) Set {
	keys := make([]string, 0, len(values))
	for key := range values {
		keys = append(keys, key)
	}
	sort.Strings(keys)

	assignments := make([]Assignment, len(keys))
	for idx, key := range keys {

	}
}

func TestPostgresOnConstraint(t *testing.T) {
	if DB.Dialector.Name() != "postgres" {
		t.Skip()
	}

	type Thing struct {
		gorm.Model
		SomeID  string
		OtherID string
		Data    string
	}

	DB.Migrator().DropTable(&Thing{})
	DB.Migrator().CreateTable(&Thing{})