DataMart extract 0 data

Dear all,

I have encountered a strange problem that the datamart

extract 0 data. I use RSRV check the infocube, there is no problem, the data in the infocube and the generated export datasource are OK. If i delete all the data and SID of D tables and F table ,and load data in the infocube, then generate export datasource again, i think the datamart should extract data.But the issure ocurred at the Product system, i can not delete data at random .

Could anybody give me a good suggestion? Thank very much!

Best regards

Alpha