To Run Entire Session in specific Isolation Lev

--add this line in the beginning of the all the commands set transaction isolation level isolationlevelname
--ex: set transaction isolation level read committed
--Isolation levels:
 --pesimistic:
 --read committed
 --read uncommitted
 --repeatable read
 --serializable
 --optimistic:
 --snapshot
 --snapshot read committed

--to use snapshot isolation level, first turn on setting called "allow snapshot isolation" @ db level settings and also add the command in the query window.
--to use snapshot read committed, turn on setting called "is read committed snapshot on" @ db level.