Forcing joins to be done separately

Question

Is there a way to prevent OWB from combining joins when generating mappings? We have a case were we need to join two tables together and then do an outer join on that result to a third table.
select join.col1, join.col2, c.col3
from (select a.col1, b.col2
from table1 a, table2 b
where a.col1=b.col1) join,
table3 c
where join.col1=c.col1(+)
and join.col2=c.col2(+)
Unforuntately, after creating the mapping using two join operators the SQL generated looks like this ...
select a.col1, b.col2, c.col3
from table1 a, table2 b, table3 c
where a.col1=c.col1(+)
and b.col2=c.col2(+)
As a result, we get this error during execution: "ORA-01417: a table may be outer joined to at most one other table"

Answer 1

Hi,
I had a similar problem with lookups:
Problem with lookups and outer joins
There are two workarounds for your problem that I'm aware of:
1) Insert a sort (or aggregator) between the two joins. This does unfortunately have a performance impact
2) Create a view to resolve one of the two joins. No performance impact, but not very elegant as you have to move "ETL logic" from the model (mapping) down into the database.
Question for development; Is there a reason why separate joins are not always resolved as inline views?
Roald