Dealing with Databases
Integration issues are probably most noticeable with databases. The most common situation is generating reports in an Office application such as Excel from data generated by an open source database such as MySQL.
In some cases, most of the company uses Windows and some areas use open source products. This is especially common with technical departments. Often, the technical people will put together applications using open source software because it avoids the licensing issues associated with Windows applications. But sooner or later the part of the company that runs on Windows is likely to need at least some of the information from that application.
Another increasingly common situation is a mix of Windows and open source databases interacting tightly in the same organization. Part of a web application’s database may be on a Windows application and the rest on an open source database. Typically, integrating the two involves replicating or updating the data between the Windows and the open source database at frequent intervals to keep them in sync. Legacy systems often support a considerable investment in applications to process the data, while the open source system is used to handle queries against the data. This setup complicates life, but open source advocates claim it can save a significant amount of money for the enterprise without requiring it to abandon its investment in proprietary databases.
MySQL AB, the company that supports MySQL, has a white paper on the subject called "Database Tiering: Achieving Scale-Out by Combining MySQL with your Existing Databases" available on their web site. In spite of the title, the information is fairly generic. (MySQL.com registration is required to access the white paper.)