Concurrent request

Question

Hi,

 

i am working on ASP.NET application (ADO.NET as data layer). Back end we are using oracle. The idea is when the user clicks on save button then in the oracle DB, we are generating the Document No. (max+1 of a DocNo column).

 

imagine, if 100 users click save button at same time, will it give same document no. to all 100 users? or is it like IIS handles one request at a time?