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用Visual C++开发数据库程序(5) if (retcode == SQL_SUCCESS &brVBar¦ retcode == SQL_SUCCESS_WITH_INFO) { /* Set the ODBC version environment attribute */ retcode = SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0); if (retcode == SQL_SUCCESS ¦¦ retcode == SQL_SUCCESS_WITH_INFO) { /* Allocate connection handle */ retcode = SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc); if (retcode == SQL_SUCCESS ¦¦ retcode == SQL_SUCCESS_WITH_INFO) { /* Set login timeout to 5 seconds. */ SQLSetConnectAttr(hdbc, (void*)SQL_LOGIN_TIMEOUT, 5, 0); /* Connect to data source */ retcode = SQLConnect(hdbc, (SQLCHAR*) "Sales", SQL_NTS, (SQLCHAR*) "JohnS", SQL_NTS, (SQLCHAR*) "Sesame", SQL_NTS); if (retcode == SQL_SUCCESS ¦¦ retcode == SQL_SUCCESS_WITH_INFO){ /* Allocate statement handle */ retcode = SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmt); if (retcode == SQL_SUCCESS ¦¦ retcode == SQL_SUCCESS_WITH_INFO) { /* Process data */; SQLFreeHandle(SQL_HANDLE_STMT, hstmt); } SQLDisconnect(hdbc); } SQLFreeHandle(SQL_HANDLE_DBC, hdbc); } } SQLFreeHandle(SQL_HANDLE_ENV, henv); SQLDriveConnect 函数SQLDriveConnect用一个连接字符串建立至数据源的连接。它可以提供比SQLConnect函数的三个参数更多的信息,可以让用户输入必要的连接信息。 如果连接建立,该函数返回完整的字符串,应用程序可使用该连接字符串建立另外的连接。 函数格式: SQLRETURN SQLDriverConnect(SQLHDBC ConnectionHandle,SQLHWND WindowHandle,SQLCHAR InConnectionString,SQLSMALLINT StringLength1,SQLCHAR OutConnetionString,SQLSMALLINT BufferLength,SQLSMALLINT *StringLength2Ptr,SQLSMALLINT DriverCompletion); 参数: ConnectionHandle 连接句柄 WindowHandle 窗口句柄,应用程序可以用父窗口的句柄,或用NULL指针 InConnectionString 连接字符串长度 OutConnectionString 一个指向连接字符中的指针 BufferLength 存放连接字符串的缓冲区的长度
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