mirror of
https://gitee.com/johng/gf.git
synced 2024-12-10 21:18:14 +08:00
153 lines
4.3 KiB
Go
153 lines
4.3 KiB
Go
// Copyright 2017 gf Author(https://gitee.com/johng/gf). All Rights Reserved.
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//
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// This Source Code Form is subject to the terms of the MIT License.
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// If a copy of the MIT was not distributed with this file,
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// You can obtain one at https://gitee.com/johng/gf.
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/*
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@author wenzi1<liyz23@qq.com>
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@date 20181109
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说明:
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1.需要导入sqlserver驱动: github.com/denisenkom/go-mssqldb
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2.不支持save/replace方法
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3.不支持LastInsertId方法
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*/
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package gdb
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import (
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"database/sql"
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"fmt"
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"gitee.com/johng/gf/g/util/gregex"
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"strconv"
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"strings"
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)
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// 数据库链接对象
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type dbMssql struct {
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*dbBase
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}
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// 创建SQL操作对象
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func (db *dbMssql) Open(config *ConfigNode) (*sql.DB, error) {
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source := ""
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if config.Linkinfo != "" {
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source = config.Linkinfo
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} else {
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source = fmt.Sprintf("user id=%s;password=%s;server=%s;port=%s;database=%s;encrypt=disable",
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config.User, config.Pass, config.Host, config.Port, config.Name)
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}
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if db, err := sql.Open("sqlserver", source); err == nil {
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return db, nil
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} else {
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return nil, err
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}
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}
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// 获得关键字操作符
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func (db *dbMssql) getChars () (charLeft string, charRight string) {
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return "\"", "\""
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}
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// 在执行sql之前对sql进行进一步处理
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func (db *dbMssql) handleSqlBeforeExec(query string) string {
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index := 0
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str, _ := gregex.ReplaceStringFunc("\\?", query, func(s string) string {
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index++
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return fmt.Sprintf("@p%d", index)
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})
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str, _ = gregex.ReplaceString("\"", "", str)
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return db.parseSql(str)
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}
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//将MYSQL的SQL语法转换为MSSQL的语法
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//1.由于mssql不支持limit写法所以需要对mysql中的limit用法做转换
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func (db *dbMssql) parseSql(sql string) string {
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//下面的正则表达式匹配出SELECT和INSERT的关键字后分别做不同的处理,如有LIMIT则将LIMIT的关键字也匹配出
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patten := `^\s*(?i)(SELECT)|(LIMIT\s*(\d+)\s*,\s*(\d+))`
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if gregex.IsMatchString(patten, sql) == false {
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fmt.Println("not matched..")
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return sql
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}
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res, err := gregex.MatchAllString(patten, sql)
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if err != nil {
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fmt.Println("MatchString error.", err)
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return ""
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}
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index := 0
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keyword := strings.TrimSpace(res[index][0])
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keyword = strings.ToUpper(keyword)
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index++
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switch keyword {
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case "SELECT":
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//不含LIMIT关键字则不处理
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if len(res) < 2 || (strings.HasPrefix(res[index][0], "LIMIT") == false && strings.HasPrefix(res[index][0], "limit") == false) {
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break
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}
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//不含LIMIT则不处理
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if gregex.IsMatchString("((?i)SELECT)(.+)((?i)LIMIT)", sql) == false {
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break
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}
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//判断SQL中是否含有order by
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selectStr := ""
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orderbyStr := ""
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haveOrderby := gregex.IsMatchString("((?i)SELECT)(.+)((?i)ORDER BY)", sql)
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if haveOrderby {
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//取order by 前面的字符串
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queryExpr, _ := gregex.MatchString("((?i)SELECT)(.+)((?i)ORDER BY)", sql)
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if len(queryExpr) != 4 || strings.EqualFold(queryExpr[1], "SELECT") == false || strings.EqualFold(queryExpr[3], "ORDER BY") == false{
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break
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}
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selectStr = queryExpr[2]
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//取order by表达式的值
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orderbyExpr, _ := gregex.MatchString("((?i)ORDER BY)(.+)((?i)LIMIT)", sql)
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if len(orderbyExpr) != 4 || strings.EqualFold(orderbyExpr[1], "ORDER BY") == false || strings.EqualFold(orderbyExpr[3], "LIMIT") == false{
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break
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}
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orderbyStr = orderbyExpr[2]
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} else {
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queryExpr, _ := gregex.MatchString("((?i)SELECT)(.+)((?i)LIMIT)", sql)
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if len(queryExpr) != 4 || strings.EqualFold(queryExpr[1], "SELECT") == false || strings.EqualFold(queryExpr[3], "LIMIT") == false{
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break
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}
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selectStr = queryExpr[2]
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}
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//取limit后面的取值范围
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first, limit := 0, 0
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for i := 1; i < len(res[index]); i++ {
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if len(strings.TrimSpace(res[index][i])) == 0 {
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continue
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}
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if strings.HasPrefix(res[index][i], "LIMIT") || strings.HasPrefix(res[index][i], "limit") {
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first, _ = strconv.Atoi(res[index][i+1])
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limit, _ = strconv.Atoi(res[index][i+2])
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break
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}
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}
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if haveOrderby {
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sql = fmt.Sprintf("SELECT * FROM (SELECT ROW_NUMBER() OVER (ORDER BY %s) as ROWNUMBER_, %s ) as TMP_ WHERE TMP_.ROWNUMBER_ > %d AND TMP_.ROWNUMBER_ <= %d", orderbyStr, selectStr, first, limit)
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} else {
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if first == 0 {
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first = limit
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} else {
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first = limit - first
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}
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sql = fmt.Sprintf("SELECT * FROM (SELECT TOP %d * FROM (SELECT TOP %d %s) as TMP1_ ) as TMP2_ ", first, limit, selectStr)
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}
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default:
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}
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return sql
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} |