Oracle SQLPlus taking exclusive session and not allowing to run update statements from .Net application

I connected via sqlplus like following: sqlplus user/password@SID I have a .Net application which also connects to same DB using same user and password. But once sqlplus is connected, it was unable to run any update statements. So, the following code doesn't do anything. It just hangs and control is not returned to program if I check it using breakpoint. command.ExecuteNonQuery() Does sqlplus take exclusive session once connected?