Create two or more data sources and mapping to DSO

I´m using SAP Netweaver BI 7.0.
If there are two or three data sources which have to be mapped to DSO which field from Data Sources has to be mapped to which field in DSO?
Is it possible to have only one DSO or should it be three DSOs because of the three Data Sources?
The thing is I have created one view out of three tables. For the view I have created one DSO. Everything worked fine. But now the requirements have changed because of currencies.
The view I have created is now mixing currencies because in the view is only one currency field, which is filled from the three tables. Two tables have different currencies and one table has one currency.
The one currency of the one table is important and should stay like it is.
I´m thinking about something like three different currency key fields in DSO which are mapped from data source. Also for every field of data source mapping with corresponding field in DSO.
Some hints? I have found articles in SDN about creating data sources and so on but they don´t help me in this matter.
Thank you in advance!


Thank you guys for explaining! I´m new to SAP BW and trying to better understand.
I`ll try it also with the view. It sounds "easier".
But if I´m doing it with the 3 data sources, that means that for each currency field of the data source I will need an corresponding currency field in the DSO for mapping.
Is it possible to have 3 times the 0Currency field in the DSO and each data source currency field will be mapped to the DSO?
If that would work the 0Currency has to be contained in the key figures.
But if the 0Currency is contained in each key figure will the assignment of currency work correct?
+For example:+
Data Source1:
Turnover in Euro.
(All currency is in Euro)
Data Source2:
Profit in Dollar.
Profit in Euro.
Profit in Yen.
Profit in different currencies available.
Data Source3:
Sales in Dollar.
Sales in Euro.
Sales in Yen.
Sales in different currencies available.
For mapping from DataSources to DSO if it is possible to have 3 times 0Currency in DSO:
Data Source1 currency fiield ---> DSO 0Currency
Data Source2 currency fiield ---> DSO 0Currency
Data Source3 currency fiield ---> DSO 0Currency
Does it make sense?