I have one problem , and I can't find the solution.
I built manually database, that has 2 tablespaces (system and user01).
I can start it up, and connect as internal.
When I use SELECT with V$ dynamic requests, it's working.
select * from v$tablespace;
it returne:
0 System
1 User01

But, when I try to run SELECT DBA_something, it returns error:
select * from dba_data_files;

ERROR at line 1
ORA 00942: table or view does not exist.

And request that consist of SELECT * from dba_somethink return same error?!!!

Perhaps it looks silly, but I can't find the explanations (I just begin to study Oracle).
Can somebody help me?

Thank you.
Best regards.