Optimize parse constraint (#4153)

* for Config.cacheStore store PreparedStmtDB key

* invalid db error and value and invalid value length error (#4151)

* support named params in Select API  (#4142)

* adds support for named arguments in select

* changes clause identifies and adds test

* optimize match english letters and midline

Co-authored-by: Ratan Phayade <ratanphayade@users.noreply.github.com>

Author: daheige

schema/check.go

@@ -6,8 +6,8 @@ import (
 )
 
 var (
-	// match English letters and midline
-	regEnLetterAndmidline = regexp.MustCompile("^[A-Za-z-_]+$")
+	// reg match english letters and midline
+	regEnLetterAndMidline = regexp.MustCompile("^[A-Za-z-_]+$")
 )
 
 type Check struct {
@@ -22,7 +22,7 @@ func (schema *Schema) ParseCheckConstraints() map[string]Check {
 	for _, field := range schema.FieldsByDBName {
 		if chk := field.TagSettings["CHECK"]; chk != "" {
 			names := strings.Split(chk, ",")
-			if len(names) > 1 && regEnLetterAndmidline.MatchString(names[0]) {
+			if len(names) > 1 && regEnLetterAndMidline.MatchString(names[0]) {
 				checks[names[0]] = Check{Name: names[0], Constraint: strings.Join(names[1:], ","), Field: field}
 			} else {
 				if names[0] == "" {

schema/relationship.go

@@ -3,7 +3,6 @@ package schema
 import (
 	"fmt"
 	"reflect"
-	"regexp"
 	"strings"
 
 	"github.com/jinzhu/inflection"
@@ -536,7 +535,11 @@ func (rel *Relationship) ParseConstraint() *Constraint {
 		settings = ParseTagSetting(str, ",")
 	)
 
-	if idx != -1 && regexp.MustCompile("^[A-Za-z-_]+$").MatchString(str[0:idx]) {
+	// 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,
+	// it only needs to be done once outside, so optimization is done here.
+	if idx != -1 && regEnLetterAndMidline.MatchString(str[0:idx]) {
 		name = str[0:idx]
 	} else {
 		name = rel.Schema.namer.RelationshipFKName(*rel)