mysql++读写BLOB数据
1、使用sql_create_n宏函数，建立数据库表字段与对象。
#define sql_create_2(NAME, CMP, CONTR, T1, I1, T2, I2) \
sql_create_complete_2(NAME, CMP, CONTR, T1, I1, #I1, T2, I2, #I2) \
//NAME：表名；CMP：比较函数；CONTR：构造函数；T1:字段类型；I1:字段名；T2:字段类型；I2:字段名
2、写数据
1）获取Query
2）inset 插入上面定义对象得实例
3）execute执行
3、读数据
1）获取Query
2）执行sql，query.store()
3）获取数据，将数据赋值到对象实例中。
mysqlpp::Query query = pConn->query();
query << szSql;
mysqlpp::StoreQueryResult res = query.store();
t_electronicWaybill waybill = res[0]; //查询一条记录
完整代码
sql_create_5(t_electronicWaybill, 1,2, mysqlpp::sql_int, id, mysqlpp::sql_int_unsigned, device_id, mysqlpp::sql_blob_null, waybill_data, mysqlpp::sql_int, waybill_datasize, mysqlpp::sql_datetime, currenttime) //插入运单 bool InsertElectronicWaybill(unsigned int nDeviceId, char *pData, int nDataSize, char *pCurrentTime) { bool bSuccess = false; mysqlpp::Connection* pConn = GetConnection(); //从连接池中获取一个连接 if (pConn == NULL) { return false; } t_electronicWaybill waybill; waybill.waybill_data.data.assign(pData,nDataSize); waybill.waybill_datasize = nDataSize; waybill.device_id = nDeviceId; waybill.id = 0; int nYear = 0, nMonth = 0, nDay = 0, nHour = 0, nMinute = 0, nSecond = 0; try { sscanf(pCurrentTime, "%d-%d-%d %d:%d:%d",&nYear,&nMonth,&nDay,&nHour,&nMinute,&nSecond); } catch(...){ } mysqlpp::DateTime *pDateTimeTemp = new mysqlpp::DateTime(nYear,nMonth,nDay,nHour,nMinute,nSecond); waybill.currenttime = *pDateTimeTemp; mysqlpp::Query query = pConn->query(); query.insert(waybill); mysqlpp::SimpleResult res; try { res = query.execute(); bSuccess = true; } catch (mysqlpp::Exception & ex) { OutputDebugString(ex.what()); } if (pDateTimeTemp != NULL) { delete pDateTimeTemp; } ReleaseConnection(pConn); //释放连接 return bSuccess; } //查询运单 bool QueryElectronicWaybill(unsigned int uiRecordId, unsigned int & nDeviceId, char *pData, int & nDataSize, char *pCurrentTime) { bool bSuccess = false; mysqlpp::Connection* pConn = GetConnection(); //从连接池中获取一个连接 if (pConn == NULL) { return false; } char szSql[256] = { 0 }; sprintf_s(szSql, "select * from t_electronicWaybill where id = %u", uiRecordId); try { mysqlpp::Query query = pConn->query(); query << szSql; mysqlpp::StoreQueryResult res = query.store(); t_electronicWaybill waybill = res[0]; memcpy(pData, waybill.waybill_data.data, waybill.waybill_data.data.length()); nDataSize = waybill.waybill_datasize; nDeviceId = waybill.device_id; if (pCurrentTime != NULL) { sprintf_s(pCurrentTime, 23, "%04d-%02d-%02d %02d:%02d:%02d", waybill.currenttime.year(), waybill.currenttime.month(), waybill.currenttime.day(), waybill.currenttime.hour(), waybill.currenttime.minute(), waybill.currenttime.second()); } } catch (mysqlpp::Exception & ex) { OutputDebugString(ex.what()); } ReleaseConnection(pConn); //释放连接 return bSuccess; } Navicat for MySQL 查看BLOB字段内容
https://blog.csdn.net/lwei_998/article/details/41871329
