Have you tried changing the database connection string?
That is not a good idea to do nothing at all to the tables, indexes, etc... If you take a little time now, it will actually save you countless hours of troubleshooting and other issues later on. Oracle uses data types that do not exist in SQL Server, how do plan on getting around that? How do you plan on creating the indexes on each table? What about all your stored queries?
By not doing the migration one object at a time, and then moving the data, creating the indexes, and updating the stats, you will not get things to work correctly. There are so many differences between the two databases, you are asking for a lot of trouble by not taking the time now to code this properly.
How much data are you planning on moving?
Andrew SQLDBA