hi how to set query while inserting to sql table for stored procedure for perticular column if register no reaches to 32 room no value should shange.

Question

hi how to set stored procedure while inserting values to query like for example
RegisterNo,Semister and RoomNo these are columns
in one room no 32 register no s can save.if it reaches to 32 and we cant give same column name for that.?
can any one suggest me?and i want to display message in aspx that 101 room number exceeded 32 student so type other room number to save.?