also in my experience, every trigger,package,procedure and function in oracle will have to be rewritten, even when they is doing the most trivial CRUD operations, and especially because the way Oracle treats sets of data is more row-based centric , where SQL is set based centric.

those objects don't have a clean upgrade path the way tables and views do. you'll need to get a developer working on this early, because just mapping the data types and migrating the data is actually pretty straightforward.

I was in on a project that did that, the data was easily moved to development in a day, and then it was all developers on hand converting procedures to SQL server, and then changing application to see if they worked on the new RDBMS. it took several months before it was bulletproof.