There is easy way to check complete list of your SAP Oracle datafiles. You can do that using integrated oracle tool called rman.
Below are the steps:
1. Login as ora<sid> in UNIX or <sid>adm in WINDOWS.
2. Call rman tools from command prompt.
orasbe> rman
3. Connect to database target.
RMAN> connect target /
4. List the datafile using command “report schema”
RMAN> report schema;
You will be shown the complete list of your datafiles.