How to avoid Sequence Gapping in ODI Interface

Question

I have an employee table and a job map table in oracle based on the employee type/group and job type/group I need to pick up the sequence, generate id
and update employee id of employee table using ODI
employee table job table
name type group id type group sequencename seqmin seqmax
pat 1 1 1 1 seq1 1 10
dan 1 2 1 2 seq2 30 40
john 1 3 1 3 seq3 20 100
when I select the sequence using if condition or case statement or decode and call the sequence <%=snpRef.getObjectName( "L" , "My_SEQ" , "D" )%>.nextval
the sequences are creating gaps for every call.as the sequence is incrementing internally for every wrong mapping. How should I get rid of these gaps.
In oracle database we call functions in the case condition.These functions consists of the seq.nextval code and the unwanted incremental gapping is avoided.
But in the case of ODI how can we get this.
Thanks,
Vikram

Answer 1

I am facing this issue when I execute on the source or staging area.When I try toexecute on the target,the ODI
doesn't allow me to execute and gives the following warning
"A mapping executed on the target cannot reference source columns. Move this mapping on the source or the staging area.     Target Column Employeeid"
In my case I am using IKM Oracle Incremental update
the source datastore is employee table, job table and target is copy of employee table(as i need to update the employee id column with sequence numbers by picking the right sequence from job table,sequence name column)