I am new to Google Apps Script. But playing around with the Debugger,
I noticed that the following object is anchored to the "this" object.
Jdbc (the methods are listed below)
Types
ResultSet
Statement
Connection
ParameterMetaData
DatabaseMetaData
ResultSetMetaData
RowIdLifetime
To me this says that you can at access any database that interfaces with JDBC.
Considering that the scripts run on a Google server, you are probably very limited
to which database management system you can use/access.
I don't know the actual setup for an individual database management system. I
have not had to use one up unto now.
Hope this helps.