we can use merge option in webi, as like syncronization in 6.5
EX: if u open one Dp & generates the report after u select
another Dp u can link with in 2Dps same containg objects
like In 1st DP(Year,Q,Country,revenue),In 2nd
DP(Year,Q,quantity sold). --> Click Merge Option -->
automatically merge same type of dia objects.It is generated
in one report.

Merge option used for fetching more than one data providers
information into single report or block. 

For example, employee information is available in different
database like some of the information in oracle and some of
information in sql server. But you need all these info into
single report. In that time merge dimension option is used
to achieve this task. 

You need to create two universe(data provider) for each data
source and then u can merge the two data provider with
common dimension field. One thing important is u can merge
only the dimension object not measure object

In dimension object should be in same data type in both data
source. ex emp no should be number or varchar. mismatched
data type will give error.