Adding database support to Unity 3D
This is exceptionally easy no need to pay big sums for a special plugin for most cases; there are 2 major flavours I’ll talk about; both can be done quick and easy.
Method 1 local database
In this method you don’t have or don’t want to connect to a server or install a server on the clients system. The solution is a local database and there are many to choose from but you don’t need to go downloading anything special as Mono includes an implementation of Sqlite which will most likely handle all your needs for a local database.
For full details see this site (Mono-project.com)
Full blog entry here (Heathenengineering.com )