Diffrence between backend insert and front end insert into a table.

Question

I am developing a conversion program for tax exemption. For this program only ZX_EXEMPTIONS table is used to populate the data and we got confirmation from Oracle also regarding this.For inserting the data into this table we are taking the max of tax_exemption_id which is pk for this table and adding one to it and inserting into the table. But problem here is after inserting from back end we are not able to insert from front end.
It seems backend data is holding the tax_exemption_id which is suppose to reserve by front end data.Please explain the different behavior of populating of tax_exemption_id from front end and back end.

Answer 1

Hi,
i think the problem is that you are using max-value + 1 for tax_exemption_id. But as ZX_EXEMPTIONS is using sequence ZX_EXEMPTIONS_S
for primary key generation, you encounter situation that you are increasing PK Id for this table without increasing sequence value.
When trying to insert rows from front end - which probably uses sequence value - it tries to use a sequence value already used by your backend
process (which generated it by Maxvalue + 1) and would then encounter a primary key violation.
I think you should use sequence mentioned above to generate your PK Ids in backend process as well. And before doing so, check current value
of ZX_EXEMPTIONS_S, as you might need to rebuild the sequence in order to select nextval sucessfully for both frontend and backend.
Regards