data getting overwrite by another load

Hi Frnds,

I am having infoobject 0BUS_AREA which is getting loaded from source system and flat file.

From source system we are loading only field 0BUS_AREA and in transformation only this field is mapped.

From flat file we are loading 6 objects including 0BUS_AREA, while  we load the data from source system all the data getting overwrite which is loaded by flat file.

we are using BW 7.0.

Please suggest solution. Thanks.