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
