There's a lot of competition among database platform vendors. Once a platform is chosen, companies rarely change, and with good reason. The cost of the people building your application accounts for most of the resources you expend on a database system. Re-training, or replacing, is often cost-prohibitive. That hasn't stopped many companies from looking to less expensive alternatives to SQL Server, like MySQL, but I'm not sure the license savings offset all the other costs, including potential performance declines from mis-configured systems.
SQL Server has had a few competitors over the years that tried to provide compatibility and enable easy or seemless migration from SQL Server to a new database engine, but none of them seem to have been very popular.
NuoDB is the latest, providing a NewSQL, distributed cloud database that has many of the features that developers look for, but is built to integrate easily with .NET technologies, including Visual Studio, has LINQ and Entity Framwork compatibility, and runs on the Azure and AWS platforms. The company hopes it will replace SQL Server as the preferred database in the Azure IaaS cloud.
I don't know that many companies want to migrate their applications to a new platform, but I do know that there might be situations and problem domains where platforms other than SQL Server make sense. If the compatibility is close enough to limit the amount of code that has to change, it's worth looking at. The problem for this challenger, and many others, is that SQL Server has grown to include many other features, like SSIS, that companies find compelling.
Ultimately I think it's easier to stick to as few platforms as possible to allow your staff to build expertise in optimizing their code and configurations for a platform. Developers and administrators don't often become experts, but I'm not sure the situation is any better if you give them an additional platform to work with.
Steve Jones
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