mirror of
https://gitee.com/johng/gf.git
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144 lines
4.3 KiB
Go
144 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 20181026
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说明：
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1.需要导入oracle驱动： github.com/mattn/go-oci8
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2.不支持save/replace方法，可以调用这2个方法估计会报错，还没测试过,(应该是可以通过oracle的merge来实现这2个功能的，还没仔细研究)
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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 dbOracle 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 *dbOracle) Open(config *ConfigNode) (*sql.DB, error) {
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var source string
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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("%s/%s@%s", config.User, config.Pass, config.Name)
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}
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if db, err := sql.Open("oci8", 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 *dbOracle) 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 *dbOracle) 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(":%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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//由于ORACLE中对LIMIT和批量插入的语法与MYSQL不一致，所以这里需要对LIMIT和批量插入做语法上的转换
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func (db *dbOracle) 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)|(INSERT)|(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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//取limit前面的字符串
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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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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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//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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//也可以使用between,据说这种写法的性能会比between好点,里层SQL中的ROWNUM_ >= limit可以缩小查询后的数据集规模
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sql = fmt.Sprintf("SELECT * FROM (SELECT GFORM.*, ROWNUM ROWNUM_ FROM (%s %s) GFORM WHERE ROWNUM <= %d) WHERE ROWNUM_ >= %d", queryExpr[1], queryExpr[2], limit, first)
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case "INSERT":
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//获取VALUE的值，匹配所有带括号的值,会将INSERT INTO后的值匹配到，所以下面的判断语句会判断数组长度是否小于3
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valueExpr, err := gregex.MatchAllString(`(\s*\(([^\(\)]*)\))`, sql)
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if err != nil {
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return sql
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}
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//判断VALUE后的值是否有多个，只有在批量插入的时候才需要做转换，如只有1个VALUE则不需要做转换
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if len(valueExpr) < 3 {
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break
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}
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//获取INTO后面的值
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tableExpr, err := gregex.MatchString(`(?i)\s*(INTO\s+\w+\(([^\(\)]*)\))`, sql)
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if err != nil {
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return sql
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}
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tableExpr[0] = strings.TrimSpace(tableExpr[0])
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sql = "INSERT ALL"
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for i := 1; i < len(valueExpr); i++ {
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sql += fmt.Sprintf(" %s VALUES%s", tableExpr[0], strings.TrimSpace(valueExpr[i][0]))
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}
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sql += " SELECT 1 FROM DUAL"
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default:
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}
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return sql
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}
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