PROC＋＋批量导入导出ORACLE数据库表

　　
最近在开发一个项目中，为了解决数据库ＩＯ瓶颈，不得不把数据库中的数据导出为文本文件。文本传到客户端后又要导入到数据库。本人用Ｃ＋＋Builder嵌入PROC++写了一个导入导出的DLL。假如对你有用深感荣幸！具体内容如下：

一、预备工作

计算机环境：Win 2000 PRO,Oracle 9i,C++ Builder 5.5

引入必要的ORACLE内部函数：要用的函数在$(ORACEL_HOME)\bin qlora9.dll链接库中。为了能在C++ Builder中使用，先得生成LIB：implib sqlora9.lib sqlora9.dll

二、源文件分析

//-------------------------------------------------------------------------

//加入必要的头文件

#include<vcl.h> #include<windows.h> #include<stdio.h> #include<stdlib.h> #include<string.h>

#include<time.h> #include<math.h> #include<fcntl.h> #include<io.h> #include<sys tat.h>

//说明DLL的输出函数

extern "C" _declspec(dlleXPort) int _stdcall ConnectDB(const char *Username,

                                const char *PassWord, const char *Dbname);

extern "C" _declspec(dllexport) int _stdcall ImportTxtfile(TList *LengthArray,

                                String *FieldArray, const char *TableName,

                                const char *FileName);

extern "C" _declspec(dllexport) int _stdcall ExportTxtfile(const char *Sql,

                                const char *FileName);

#pragma hdrstop

//----------------------------------------------------------------------------

#define MAX_ITEMS 20        //定义最大字段数

#define MAX_VNAME_LEN 30 //定义选择表项最大长度

#define MAX_INAME_LEN 30 //定义指示器变量名字的最大长度

EXEC SQL INCLUDE sqlca;    //说明SQL通讯区

EXEC SQL INCLUDE oraca;    //说明ORACLE通讯区

EXEC SQL INCLUDE sqlda;    //说明SQL语句描述结构/*SQLDA结构体请查相关资料*/

EXEC ORACLE OPTION (ORACA = YES);

EXEC ORACLE OPTION (RELEASE_CURSOR = YES);

//说明ORACLE外部函数

extern "C" _declspec(dllimport) void _stdcall sqlclu(SQLDA*);

extern "C" _declspec(dllimport) void _stdcall sqlnul(short*, short*, int*);

extern "C" _declspec(dllimport) void _stdcall sqlprc(int*, int*, int*);

extern "C" _declspec(dllimport) strUCt SQLDA * _stdcall sqlald(int, unsigned int, unsigned int);

SQLDA *SelectUnit; //定义选择项描述

SQLDA *BindUnit; //定义输入项空间

//定义变量，以存放连接数据库的参数

EXEC SQL BEGIN DECLARE SECTION;

    char User[20];//用户名

    char Pwd[20];//密码

    char DB[20];//数据库服务名

EXEC SQL END DECLARE SECTION;

bool bConnect = false;//是否连接标志

#pragma hdrstop

#pragma argsused

//C++ Builder DLL的主函数

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fwdreason, LPVOID lpvReserved)

{

        return 1;

}

/*---------------------------------------------------------------------------

    连接数据库

---------------------------------------------------------------------------*/

int _stdcall ConnectDB(const char *Username, const char *Password,

                                   const char *Dbname)

{

strcpy(User, Username);

strcpy(Pwd, Password);

strcpy(DB, Dbname);

EXEC SQL CONNECT :User IDENTIFIED BY :Pwd USING :DB;

if (sqlca.sqlcode < 0)

    return -1;

bConnect = true;

return 0;

}

/*---------------------------------------------------------------------------

导出文本函数

因为不确定SELECT语句的表及字段，所以我使用动态语句(ORACLE DYNAMIC SQL)的//第四种方式。
动态SQL方法四是在不确定SQL语句的选择项与输入项，且不知个数与数据类型的情况下使用的一种复杂程序设计技术。

---------------------------------------------------------------------------*/

int _stdcall ExportTxtfile(const char *Sql/*SQL选择语句*/, const char FileName/*导出目标文本文件名*/)

{

int null_ok, precision, scale;

int handle;

if ((handle = open(FileName, O_CREATO_TEXTO_APPENDO_RDWR, S_IREADS_IWRITE)) == -1)

{

    //文件打开出错

    return -1;

}

//定义变量，以存放SQL语句

EXEC SQL BEGIN DECLARE SECTION;

    char sqlstr[256];

EXEC SQL END DECLARE SECTION;

//检查是否连接数据库

if (bConnect == false) return -2;

strcpy(sqlstr/*.arr*/, Sql);

// sqlstr.len = strlen(sql);

//给描述区分配空间

if ((SelectUnit = sqlald(MAX_ITEMS, MAX_VNAME_LEN, MAX_INAME_LEN)) == (SQLDA *)NULL)

{

    //空间分配失败

    return -3;

}

if ((BindUnit = sqlald(MAX_ITEMS, MAX_VNAME_LEN, MAX_INAME_LEN)) == (SQLDA *)NULL)

{

    //空间分配失败

    return -3;

}

//给查询返回值存储区分配空间

SelectUnit->N = MAX_ITEMS;

for (int i=0; i < MAX_ITEMS; i++)

{

    BindUnit->I[i] = (short *)malloc(sizeof(short *));

    BindUnit->V[i] = (char *)malloc(MAX_VNAME_LEN);

}

for (int i=0; i < MAX_ITEMS; i++)

{

    SelectUnit->I[i] = (short *)malloc(sizeof(short *));

    SelectUnit->V[i] = (char *)malloc(MAX_VNAME_LEN);

}

EXEC SQL WHENEVER SQLERROR GOTO sqlerr;//DO sql_error("导出出错");

//设置ＳＱＬ语句

EXEC SQL PREPARE SQLSA FROM :sqlstr;

EXEC SQL DECLARE Cursorbase CURSOR FOR SQLSA;

//输入描述处理

BindUnit->N = MAX_ITEMS;

EXEC SQL DESCRIBE BIND VARIABLES for SQLSA INTO BindUnit;

if (BindUnit->F < 0)

{

    return -4;

    //输入项过多

}

BindUnit->N = BindUnit->F;

//打开光标

EXEC SQL OPEN Cursorbase USING DESCRIPTOR BindUnit;

//选择项处理

EXEC SQL DESCRIBE SELECT LIST for SQLSA INTO SelectUnit;

if (SelectUnit->F < 0)

{

    return -4;

    //选择表项过多

}

SelectUnit->N = SelectUnit->F;

//因为所有格式，类型都是不确定的，所以要得到正确的返回值就要处理格式

for (int i=0; i < SelectUnit->F; i++)

{

    sqlnul(&(SelectUnit->T[i]), &(SelectUnit->T[i]), &null_ok);

    switch (SelectUnit->T[i])

    {

           case 1://CHAR

                break;

           case 2://NUMBER

                sqlprc(&(SelectUnit->L[i]), &precision, &scale);

                if (precision == 0)

                  precision = 40;

                SelectUnit->L[i] = precision + 2;

                break;

        case 8://LONG

             SelectUnit->L[i] = 240;

             break;

        case 11://ROWID

             SelectUnit->L[i] = 18;

             break;

        case 12://DATE

             SelectUnit->L[i] = 9;

             break;

        case 23://RAW

             break;

        case 24://LONGRAW

             SelectUnit->L[i] = 240;

             break;

     }

     SelectUnit->V[i] = (char *)realloc(SelectUnit->V[i], SelectUnit->L[i]+1);

     SelectUnit->T[i] = 1;//把所有类型转换为字符型

}

EXEC SQL WHENEVER NOT FOUND goto EndFor;

for (;;)

{

    EXEC SQL FETCH Cursorbase USING DESCRIPTOR SelectUnit;

    //输出各字段

    for (int i=0; i < SelectUnit->F; i++)

    {

      char buffer[256];

      if (i != SelectUnit->F-1)

        sprintf(buffer, "%s", SelectUnit->V[i]);

      else sprintf(buffer, "%s\r\n", SelectUnit->V[i]);

      int length = strlen(buffer);

      if (write(handle, buffer, length) != length)

      {

        return -5;

        //写文件失败 exit(1);

      }

    }

}

EndFor:

close(handle);

for (int i=0; i < MAX_ITEMS; i++)

{

    if (SelectUnit->V[i] != (char *)NULL)

      free(SelectUnit->V[i]);

    free(SelectUnit->I[i]);

}

for (int j=0; j < MAX_ITEMS; j++)

{

    if (BindUnit->V[j] != (char *)NULL)

      free(BindUnit->V[j]);

    free(BindUnit->I[j]);

}

sqlclu(SelectUnit);

sqlclu(BindUnit);

EXEC SQL CLOSE Cursorbase;

return 0;

sqlerr:

return -6;

}

/*----------------------------------------------------------------------------

导入文本

为了批量导入，在此我调用的sqlldr工具

首先生成SQL*Loader控制文件，后运行sqlldr

----------------------------------------------------------------------------*/

int _stdcall ImportTxtfile(TList LengthArray/*导入文本的字段长度链表*/,

String *FieldArray/*数据库表的了段名数组*/, const char TableName/*导入的目标表*/, const char FileName/*导入的源文本文件*/)

{

//产生SQL*Loader控制文件

FILE *fout, *fp;

char Execommand[256];

char sqlload[] = ".\ qlload.ctl";

//检查是否连接数据库

if (bConnect == false) return -2;

if ((fout=fopen(sqlload, "w")) == NULL)

{

    //建立控制文件出错

    return -1 ;

}

fprintf(fout, "LOAD DATA\n");

fprintf(fout, "INFILE '%s'\n", FileName);

fprintf(fout, "APPEND INTO TABLE %s (\n", TableName);

int iStart = 1;

for(int i=0; i < LengthArray->Count; i++)

{

    fprintf(fout, "%11s POSITION(%d:%d)", FieldArray[i], iStart, *(int*)LengthArray->Items[i]+iStart-1);

    iStart += *(int*)LengthArray->Items[i];

    fprintf(fout, " CHAR");

    if(i < LengthArray->Count-1)

      fprintf(fout, ",\n");

}

fprintf(fout, ")\n");

fclose(fout);

sprintf(Execommand, "sqlldr.exe userid=%s/%s@%s control=%s",

                      User, Pwd, DB, sqlload);

if (system(Execommand) == -1)

{

    //SQL*Loader执行错误

    return -1;

}

return 0 ;

}

//----------------------------------------------------------------------------

三、编译

用ORACLE的PROC预编译器预编后，放入C++ Builder中联编。
联编时需加入前面生成的sqlora9.lib。联编时还要注重，所有PROC生成的ORACLE内部函数调用都要说明为extern "C" _declspec(dllexport) TYPE _stdcall类型。

水平有限还请见谅！！！请多多指点。ＱＱ：5005647