slimdave:

now the discussion is diverting....the question was not if its logical to have PK of varchar or number....

Question was Whether PK of varchar wud hinder the performance...

and obiviously yes....as compared to PKs with numbers...

Wat i gave the example there is just to illustrate the fact that insert or update with varchar as Pk would take more time...

And s ....u can logically comprehend that by extrapolating the graph (from above example)....with many records, say 1 lackh, in table & trying to update/insert ...u will suerly have to wait for say 30secs to 1 row to be updated/inserted sucessfully.

If it were a numeric type , i bet , it wud jus take 2 to 3 secs to update/insert with same number of recs as above..i.e 1 lackh..

Abhay.