"Oslo" is the former code name for a set of Microsoft modeling technologies that aimed to provide productivity gains across the lifecycle of .NET Framework applications. It was first announced in October 2007 and early Community Technology Previews (CTPs) of the technology have been released in October 2008, January 2009, May 2009, and November 2009.

By November 2009, various components of the original "Oslo" vision had been released under other names. The remaining pieces, namely the Repository/SQL Server Modeling Services, code name "Quadrant," and the code name "M" language, were collectively called the "SQL Server Modeling CTP." However, in September 2010 Microsoft announced that it would no longer be investing in "Quadrant" and the Repository, but is still exploring options for the "M" language.

Details of this announcement can be found on the SQL Server Modeling team blog: http://blogs.msdn.com/b/modelcitizen/archive/2010/09/22/update-on-sql-server-modeling-ctp-repository-modeling-services-quot-quadrant-quot-and-quot-m-quot.aspx.