优化func (session *Session) slice2Bean方法中的strings.ToLower（对应issue:https://gitea.com/xorm/xorm/issues/2243）

rows.go

@@ -129,7 +129,9 @@ func (rows *Rows) Scan(beans ...interface{}) error {
 		return err
 	}
 
-	if err := rows.session.scan(rows.rows, rows.session.statement.RefTable, beanKind, beans, types, fields); err != nil {
+	allColumn := ParseQueryRows(fields, types)
+
+	if err := rows.session.scan(rows.rows, rows.session.statement.RefTable, beanKind, beans, allColumn, types, fields); err != nil {
 		return err
 	}
 

session.go

@@ -16,8 +16,6 @@ import (
 	"io"
 	"reflect"
 	"strconv"
-	"strings"
-
 	"xorm.io/xorm/contexts"
 	"xorm.io/xorm/convert"
 	"xorm.io/xorm/core"
@@ -418,7 +416,7 @@ func getField(dataStruct *reflect.Value, table *schemas.Table, colName string, i
 // Cell cell is a result of one column field
 type Cell *interface{}
 
-func (session *Session) rows2Beans(rows *core.Rows, fields []string, types []*sql.ColumnType,
+func (session *Session) rows2Beans(rows *core.Rows, allColumn *AllColumn, fields []string, types []*sql.ColumnType,
 	table *schemas.Table, newElemFunc func([]string) reflect.Value,
 	sliceValueSetFunc func(*reflect.Value, schemas.PK) error,
 ) error {
@@ -428,11 +426,11 @@ func (session *Session) rows2Beans(rows *core.Rows, fields []string, types []*sq
 		dataStruct := newValue.Elem()
 
 		// handle beforeClosures
-		scanResults, err := session.row2Slice(rows, fields, types, bean)
+		scanResults, err := session.row2Slice(rows, allColumn, fields, types, bean)
 		if err != nil {
 			return err
 		}
-		pk, err := session.slice2Bean(scanResults, fields, bean, &dataStruct, table)
+		pk, err := session.slice2Bean(scanResults, allColumn, fields, bean, &dataStruct, table)
 		if err != nil {
 			return err
 		}
@@ -447,7 +445,7 @@ func (session *Session) rows2Beans(rows *core.Rows, fields []string, types []*sq
 	return rows.Err()
 }
 
-func (session *Session) row2Slice(rows *core.Rows, fields []string, types []*sql.ColumnType, bean interface{}) ([]interface{}, error) {
+func (session *Session) row2Slice(rows *core.Rows, allColumn *AllColumn, fields []string, types []*sql.ColumnType, bean interface{}) ([]interface{}, error) {
 	for _, closure := range session.beforeClosures {
 		closure(bean)
 	}
@@ -705,7 +703,7 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 	return convert.AssignValue(fieldValue.Addr(), scanResult)
 }
 
-func (session *Session) slice2Bean(scanResults []interface{}, fields []string, bean interface{}, dataStruct *reflect.Value, table *schemas.Table) (schemas.PK, error) {
+func (session *Session) slice2Bean(scanResults []interface{}, allColum *AllColumn, fields []string, bean interface{}, dataStruct *reflect.Value, table *schemas.Table) (schemas.PK, error) {
 	defer func() {
 		executeAfterSet(bean, fields, scanResults)
 	}()
@@ -714,19 +712,18 @@ func (session *Session) slice2Bean(scanResults []interface{}, fields []string, b
 
 	tempMap := make(map[string]int)
 	var pk schemas.PK
-	for i, colName := range fields {
+	for i, field := range allColum.Fields {
 		var idx int
-		lKey := strings.ToLower(colName)
 		var ok bool
 
-		if idx, ok = tempMap[lKey]; !ok {
+		if idx, ok = tempMap[field.LowerFieldName]; !ok {
 			idx = 0
 		} else {
 			idx++
 		}
-		tempMap[lKey] = idx
+		tempMap[field.LowerFieldName] = idx
 
-		col, fieldValue, err := getField(dataStruct, table, colName, idx)
+		col, fieldValue, err := getField(dataStruct, table, field.FieldName, idx)
 		if _, ok := err.(ErrFieldIsNotExist); ok {
 			continue
 		} else if err != nil {

session_find.go

@@ -5,8 +5,10 @@
 package xorm
 
 import (
+	"database/sql"
 	"errors"
 	"reflect"
+	"strings"
 
 	"xorm.io/builder"
 	"xorm.io/xorm/caches"
@@ -161,6 +163,36 @@ func (session *Session) find(rowsSlicePtr interface{}, condiBean ...interface{})
 	return session.noCacheFind(table, sliceValue, sqlStr, args...)
 }
 
+type QueryedField struct {
+	FieldName      string
+	LowerFieldName string
+	ColumnType     *sql.ColumnType
+}
+
+type AllColumn struct {
+	Fields     []*QueryedField
+	FieldNames []string
+	Types      []*sql.ColumnType
+}
+
+func ParseQueryRows(fieldNames []string, types []*sql.ColumnType) *AllColumn {
+	var allColumn AllColumn
+
+	fields := make([]*QueryedField, 0, len(fieldNames))
+
+	for i, fieldName := range fieldNames {
+		field := &QueryedField{
+			FieldName:      fieldName,
+			LowerFieldName: strings.ToLower(fieldName),
+			ColumnType:     types[i],
+		}
+		fields = append(fields, field)
+	}
+
+	allColumn.Fields = fields
+	return &allColumn
+}
+
 func (session *Session) noCacheFind(table *schemas.Table, containerValue reflect.Value, sqlStr string, args ...interface{}) error {
 	elemType := containerValue.Type().Elem()
 	var isPointer bool
@@ -188,6 +220,8 @@ func (session *Session) noCacheFind(table *schemas.Table, containerValue reflect
 		return err
 	}
 
+	allColumn := ParseQueryRows(fields, types)
+
 	newElemFunc := func(fields []string) reflect.Value {
 		return utils.New(elemType, len(fields), len(fields))
 	}
@@ -238,7 +272,7 @@ func (session *Session) noCacheFind(table *schemas.Table, containerValue reflect
 		if err != nil {
 			return err
 		}
-		err = session.rows2Beans(rows, fields, types, tb, newElemFunc, containerValueSetFunc)
+		err = session.rows2Beans(rows, allColumn, fields, types, tb, newElemFunc, containerValueSetFunc)
 		rows.Close()
 		if err != nil {
 			return err

session_get.go

@@ -164,7 +164,9 @@ func (session *Session) nocacheGet(beanKind reflect.Kind, table *schemas.Table,
 		return true, err
 	}
 
-	if err := session.scan(rows, table, beanKind, beans, types, fields); err != nil {
+	allColumn := ParseQueryRows(fields, types)
+
+	if err := session.scan(rows, table, beanKind, beans, allColumn, types, fields); err != nil {
 		return true, err
 	}
 	rows.Close()
@@ -172,7 +174,7 @@ func (session *Session) nocacheGet(beanKind reflect.Kind, table *schemas.Table,
 	return true, session.executeProcessors()
 }
 
-func (session *Session) scan(rows *core.Rows, table *schemas.Table, firstBeanKind reflect.Kind, beans []interface{}, types []*sql.ColumnType, fields []string) error {
+func (session *Session) scan(rows *core.Rows, table *schemas.Table, firstBeanKind reflect.Kind, beans []interface{}, allColumn *AllColumn, types []*sql.ColumnType, fields []string) error {
 	if len(beans) == 1 {
 		bean := beans[0]
 		switch firstBeanKind {
@@ -180,13 +182,13 @@ func (session *Session) scan(rows *core.Rows, table *schemas.Table, firstBeanKin
 			if !isScannableStruct(bean, len(types)) {
 				break
 			}
-			scanResults, err := session.row2Slice(rows, fields, types, bean)
+			scanResults, err := session.row2Slice(rows, allColumn, fields, types, bean)
 			if err != nil {
 				return err
 			}
 
 			dataStruct := utils.ReflectValue(bean)
-			_, err = session.slice2Bean(scanResults, fields, bean, &dataStruct, table)
+			_, err = session.slice2Bean(scanResults, allColumn, fields, bean, &dataStruct, table)
 			return err
 		case reflect.Slice:
 			return session.getSlice(rows, types, fields, bean)