if err := DB.Create(&user).Error; err != nil {
		t.Fatalf("errors happened when create: %v", err)
	}

	user.Languages = []Language{{Code: "zh-CN", Name: "Chinese"}, {Code: "en", Name: "English"}}
	for _, lang := range user.Languages {
		DB.Create(&lang)
	}
	user.Friends = []*User{{Name: "friend-1"}, {Name: "friend-2"}}

	if err := DB.Save(&user).Error; err != nil {

				if matched {
					return nil
				}
			}
		}
	}

	var (
		name     string
		idx      = strings.Index(str, ",")
		settings = ParseTagSetting(str, ",")
	)

	// optimize match english letters and midline
	// The following code is basically called in for.
	// In order to avoid the performance problems caused by repeated compilation of regular expressions,

package schema

import (
	"regexp"
	"strings"

	"gorm.io/gorm/clause"
)

// reg match english letters and midline
var regEnLetterAndMidline = regexp.MustCompile(`^[\w-]+$`)

type CheckConstraint struct {
	Name       string
	Constraint string // length(phone) >= 10
	*Field
}

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

func (chk *CheckConstraint) Build() (sql string, vars []interface{}) {

	}

	// TODO(gri) This may print "unexpected X, expected Y".
	//           Consider "got X, expected Y" in this case.
	p.errorAt(pos, "syntax error: unexpected "+tok+msg)
}

// tokstring returns the English word for selected punctuation tokens
// for more readable error messages. Use tokstring (not tok.String())
// for user-facing (error) messages; use tok.String() for debugging
// output.
func tokstring(tok token) string {

		start := time.Now()
		defer func() {
			fmt.Fprintf(xLog, "%.3fs # %s\n", time.Since(start).Seconds(), text)
		}()
	}
	// TODO: Impose limits on command output size.
	// TODO: Set environment to get English error messages.
	var stderr bytes.Buffer
	var stdout bytes.Buffer
	c := exec.CommandContext(ctx, cmd[0], cmd[1:]...)
	c.Cancel = func() error { return c.Process.Signal(os.Interrupt) }
	c.Dir = dir
	c.Stdin = stdin