数据库--数据提取：ODBC源

雨点打透心脏的1/2处 2022-02-14 13:51 206阅读 0赞

转自：[https://blog.csdn.net/yuqian123455/article/details/85926347][https_blog.csdn.net_yuqian123455_article_details_85926347]

ODBC是一种标准，或则是一种封装，使得数据库有一种一致和清晰的工作方式。  
1、如何在windows中创建ODBC源？创建SQL server 的数据源

控制面板，添加到系统DSN，命名数据源名，数据源描述，输入数据库名称，测试成功，即可以使用；

2、代码读取ODBC数据源  
    // ODBC.cpp : Defines the entry point for the console application.

\#include "stdafx.h"  
\#include"windows.h"  
\#include"sql.h"  
\#include"sqlext.h"  
\#include"sqltypes.h"  
\#include<cstdlib>  
\#include<iostream>

using namespace std;  
//---end

\#pragma comment(lib, "odbc32.lib")  
/\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*   
 模  块：获取OBDC数据源数据  
 版  本：来自于MSDN  
 作  者：  
 创建日期：  
 功  能：  
 参  数：  
 返回值：  
 其  他：  
\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*/  
SQLCHAR file\_context\[102400000\]=\{0\};  
void getDavieData()  
\{  
    SQLHENV serverhenv;  
    SQLHDBC serverhdbc;  
    SQLHSTMT serverhstmt = 0;  
    SQLRETURN ret;  
    SQLCHAR file\_id\[20\]=\{0\};  
    SQLCHAR file\_type\[20\]=\{0\} ;  
    //BLOB    te\_file;  
    //SQLCHAR te\_file\[1024\]=\{0\};  
    SQLINTEGER length;  
    SQLPOINTER rgbValue = NULL;

ret = SQLAllocHandle(SQL\_HANDLE\_ENV,SQL\_NULL\_HANDLE,&serverhenv);// 分配环境句柄

ret = SQLSetEnvAttr(serverhenv,SQL\_ATTR\_ODBC\_VERSION,(void\*)SQL\_OV\_ODBC3,0);//设置环境属性  
    if(!SQL\_SUCCEEDED(ret))  
    \{  
        cout<<"AllocEnvHandle error!"<<endl;  
        system("pause");  
        return;  
    \}

ret = SQLAllocHandle(SQL\_HANDLE\_DBC,serverhenv,&serverhdbc);//分配链接句柄  
    if(!SQL\_SUCCEEDED(ret))  
    \{  
        cout<<"AllocDbcHandle error!"<<endl;  
        system("pause");  
        return;  
    \}

// Set login timeout to 5 seconds  
    ret = SQLSetConnectAttr(serverhdbc, SQL\_LOGIN\_TIMEOUT,SQLPOINTER(5), 0);

//数据库链接(serverhdbc, 数据库名称，SQL\_NTS，用户名，密码，SQL\_NTS)  
    ret = SQLConnect(serverhdbc,(SQLCHAR\*)"XX数据库名",SQL\_NTS,NULL,SQL\_NTS,NULL,SQL\_NTS);  
    if(!SQL\_SUCCEEDED(ret))  
    \{  
        SQLCHAR SQLState\[10\] =\{0\};  
        SQLINTEGER integer= 0 ;  
        SQLCHAR szText\[200\] =\{0\};  
        SQLSMALLINT nTxtLen = 0;  
        ret = SQLGetDiagRec(SQL\_HANDLE\_STMT, serverhstmt, 1, SQLState,&integer, szText,200,&nTxtLen);  
        system("pause");  
    \}    
    ret = SQLAllocHandle(SQL\_HANDLE\_STMT,serverhdbc,&serverhstmt);//分配执行语句句柄  
    //ret=SQLExecDirect(serverhstmt,(SQLCHAR\*)"SELECT \\"te\_comp\\",\\"te\_vstype\\"  FROM \\"tbadmin\\".\\"tb\_v  
    ret=SQLExecDirect(serverhstmt,(SQLCHAR\*)"SELECT \\"file\_id\\",\\"file\_type\\",\\"file\_context\\"  FROM \\"表名\\" --WHERE te\_comp = '1734893'",SQL\_NTS);//查询语句  
    if(ret == SQL\_SUCCESS || ret == SQL\_SUCCESS\_WITH\_INFO)  
    \{  
          
        ret = SQLBindCol(serverhstmt,1, SQL\_C\_CHAR, (void\*)file\_id,sizeof(file\_id), &length);//绑定数据  
        ret = SQLBindCol(serverhstmt,2, SQL\_C\_CHAR, (void\*)file\_type,sizeof(file\_type), &length);  
        //ret = SQLBindCol(serverhstmt,3, SQL\_C\_BINARY, (void\*)&te\_file,sizeof(te\_file), &length);  
          
        if(!SQL\_SUCCEEDED(ret))  
        \{  
            SQLCHAR SQLState\[10\] =\{0\};  
            SQLINTEGER integer= 0 ;  
            SQLCHAR szText\[200\] =\{0\};  
            SQLSMALLINT nTxtLen = 0;  
            ret = SQLGetDiagRec(SQL\_HANDLE\_STMT, serverhstmt, 1, SQLState,&integer, szText,200,&nTxtLen);  
            system("pause");  
        \}

CreateDirectoryA("\*\*文件名\*\*", 0); //这文件名称  
        while(SQL\_NO\_DATA != SQLFetch(serverhstmt))//循环获取数据  
        \{                
            ret = SQLGetData(serverhstmt,3, SQL\_C\_CHAR, (void\*)file\_context,sizeof(file\_context), &length);//获取数据  
            char fName\[20\] = \{0\};  
            sprintf(fName, "\*\*文件名\*\*\\\\%s\_%s", file\_id,file\_type);  
            FILE\* fp = fopen(fName, "wb");  
            fwrite(file\_context, strlen((char\*)file\_context), 1, fp);  
            fclose(fp);

if(!SQL\_SUCCEEDED(ret))  
            \{  
                SQLCHAR SQLState\[10\] =\{0\};  
                SQLINTEGER integer= 0 ;  
                SQLCHAR szText\[200\] =\{0\};  
                SQLSMALLINT nTxtLen = 0;  
                ret = SQLGetDiagRec(SQL\_HANDLE\_STMT, serverhstmt, 1, SQLState,&integer, szText,200,&nTxtLen);  
                system("pause");  
            \}     
            cout<<"name:"<<file\_id<<"  ID:"<<file\_type << "DATA: ";  
            cout<<endl;  
        \}      
    \}

//释放句柄  
    ret=SQLFreeHandle(SQL\_HANDLE\_STMT,serverhstmt);  
    if(SQL\_SUCCESS!=ret && SQL\_SUCCESS\_WITH\_INFO != ret)  
        cout<<"free hstmt error!"<<endl;

//断开数据库链接  
    ret=SQLDisconnect(serverhdbc);      
    if(SQL\_SUCCESS!=ret&&SQL\_SUCCESS\_WITH\_INFO!=ret)  
        cout<<"disconnected error!"<<endl;

//释放链接句柄  
    ret=SQLFreeHandle(SQL\_HANDLE\_DBC,serverhdbc);  
    if(SQL\_SUCCESS!=ret&&SQL\_SUCCESS\_WITH\_INFO!=ret)  
        cout<<"free hdbc error!"<<endl;

//释放环境句柄  
    ret=SQLFreeHandle(SQL\_HANDLE\_ENV,serverhenv);  
    if(SQL\_SUCCESS!=ret&&SQL\_SUCCESS\_WITH\_INFO!=ret)  
        cout<<"free henv error!"<<endl;  
    system("pause");  
\}  
\---------------------   
作者：eGanWo   
来源：CSDN   
原文：https://blog.csdn.net/yuqian123455/article/details/85926347   
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[https_blog.csdn.net_yuqian123455_article_details_85926347]: https://blog.csdn.net/yuqian123455/article/details/85926347