change user login at runtime

Hi, some one help me with this please
Our application is developed in Dot Net with Sql Server 2000 as a back
end.We have created users in our application (Dot Net) that will be
physically created in the back-end in the DB to which we will be connected
other than SA. These users will be authenticated by an administrator user to
login first time. After logging the application a tree menu appears to which
the forms and reports are attached . We are trying to implement a scenario
that the user will be given privileges of select , update, insert, delete on
the forms when they will double click it and open them. After closing the
form the privileges will be revoked from the user on the certain tables
associated with that form.
Now we cannot understand which user will be giving those privileges to the
connected user as we dont want to use SA. As this could become a problem at
the deployment time as we do not want to hard code the "SA" user. I have
seen "CONNECT To" statement that could change the login at runtime but it is
not running with these commands
EXEC SQL CONNECT TO :svr USER :usr;
Or
EXEC SQL CONNECT TO "gizmo.pubs" USER "sa";
Or
EXEC SQL CONNECT TO gizmo.pubs USER sa;
RegardsHi Shahzad:
I think you can use the connectstring to applied this.
You can change the connect string by the value you get from the asp and
change the connectstring and then connect to the sql server, I think it is
not very complexity.
Best Wishes
Wei Ci Zhou