Hi Chetanaites,
 
SAP written test is on line test conducted by merittrac. 

it contains 3 sections.

1. Aptitude: questions based on logical reasoning, easy but time killing.
                      15 ques-----------------20 min
 
2. RDBMS:  questions based on codd's rules, normalization, sql queries,
                  little bit tough to my knowledge http://www.ChetanaSinterview.com
                            20 ques.................20min

3. Optional(C/C++/Java):  mine is C, easy, concentrate on memory allocation, pointers.
                       20ques...................20min
 
(Paper Submitted By : Polireddy.P)