Obtaining "rows selected" value after custom sql query in Database adaptor

Question

We are executing a custom query in a database adaptor. With other technologies (JDBC, etc.) the result of a query will not only produce a result set but a count of the number of rows selected. E.G. the script output of Oracle SQL Developer will print out something like:
9999 rows selected
at the end of the script output.
I would like to obtain this value for a BPEL process. Of course, I could execute a 2nd query whose where clause is identical to the first, but selects count(*) instead. However, this is not only inefficient but (in rare circumstances in an active database) could be wrong.
It is not obvious to this BPEL novice how to obtain the row selected value as well as the result set in one Invoke. Is this possible?

Answer 1

This may not be the only solution - but it is how I have done it in the past.
Following the invoke step of the adapter, use an assign/copy step to populate an integer BPEL variable using the count xpath function...
<assign name="Initialize">
<copy>
<from expression="count(bpws:getVariableData('Invoke_Query_OutputVariable','MyTableQueryCollection','/ns3:MyTableQueryCollection/ns3:MyTableQuery'))"/>
<to variable="NumberOfRecordsReturned"/>
</copy>
</assign>
That should assign the number of records returned by the query.
I hope that helps.
Rod.
Edited by: Rod Tunnels on Dec 15, 2009 1:16 PM