Forum OpenACS Q&A: Response to Windows, AOLServer, and OACS
MSSQL has a ...um.. "language" of a sorts, but I wouldn't want to use it, T-SQL. Much as Rolf described PHP, T-SQL combines the worst features of several languages. OTOH, there are no doubt improvements since I last tangled with that beast, but I cannot describe such.
MSSQL has a number of small differences that can be papered over, for instance, there are no sequences, but you can create a table with an '@@IDENTITY' type for key generation.
MSSQL has no syntax for transative closures.
MSSQL, when I last saw it, has no MVCC, and they were pretty fierce about knocking any kind of optimistic locking. So a port to MSSQL will have many more opportunities for deadlocking.
In summary, most of the largest issues in an Oracle-to-MSSQL port have been solved in the Oracle-to-Postgres port. There are new issues, of course, but this is well within reach. The problem, of course, is financing.
More on Apache2 when I have more to report.