How to import XML into SQL Server database?

What is a good, free, web-friendly relational database program?

• I'm looking for a free (possibly open-source) relational database program that I can use as a data capture, analysis and decision-support tool for a multiplayer online economic and military strategy game (EVE). The basic requirements are : (1) standard SQL support, or at least an easy-to-use, intuitive RDB design and query language; (2) web-friendly GUI front-end, compatible with all standard browsers - I don't really have the time or the patience to write a front-end in, for e.g., Java or php from scratch, so it would be nice if it comes with one, but it must be customizable so I that can create bespoke data input and query screens, etc.; (3) access-control security - I don't want unauthorized users hacking into it (assuming standard firewalls might not be sufficient); (4) speed, reliability and robustness - I don't want it freezing up or crashing at mission-critical moments (e.g. combat); (5) bulk data import/export capabilities via for e.g. XML or CSV files; (6) support for distributed deployment, i.e. mutli-server mirroring with automatic synchronization (not essential, but certainly nice to have for multi-time-zone, concurrent multi-user access). (7) built-in (or Add-In) functionality for graphing, mathematical calculations and tabular output, or compatibility with common programs that offer this - e.g. MS Excel etc.   (8) cross-platform support - MS Windows, Unix/Linux, MacOS (nice to have, but certainly Windows as a mimumum). Are there any free RDB programs out there that offer most or all of these things, or am I just asking the impossible? And what other solutions might fufil these requirements at a reasonable price (and preferably none)?

• Answer:

  FOSS RDBMs technologies have come a LONG way since the 80s and 90s. They run a lot of major websites and even have UIs that help you with managing access, backing up, and so forth. A good chunk of the internet runs on these things. The two biggest modern FOSS databases are probably PostgreSQL and MySQL, although if you want to start off lightweight/prototyping, SQLite is pretty good (it's in-memory and fast, but isn't great at concurrency and doesn't scale terribly well).