The way dxdatafbook works is that there is an database that holds all the information, and dxdb reads it from there. Dxdb does not hold any data itself. It's more of a sophisticated go-between that reads all the data, constructs database queries as you need them, then executes them, and applies the properties or does comparisons as appropriate.
Dxdb can be configured to work with many flavors of database tools. Such as Microsoft Access, SQL Server, dbase, Oracle, a set of text files, or a number of others. The configuration of dxdb is normally done by a system admin, and is saved in a .dbc file. This file can be saved anywhere, but most likely can be found in the central library or somewhere near it. The path to the dbc file can be found from any DxDesigner project, under Setup > Settings > Project > xDX Datafbook. The dbc file will most likely refer to an ODBC connection, which is an operating system object that tells the OS it can use a database and provides a standardized protocol to interact with it.
(.accdb is the extension for MS Access databases from Office 2010 onwards. Before that it was .mdb)
You can right-click in dxdatabook and select Configure to see the configuration graphically.
The ODBC connection is also normally set up by a system admin on your computer. You can see them by looking in the Control Panel under Administrative Tools > Data Sources (ODBC). The properties of the ODBC object will include the location of the database and a driver for it. (One note - 64 bit systems use a different ODBC admin tool than 32 bit systems. The 64 bit version is C:\Windows\System32\odbcad32.exe, the 32 bit version is at C:\Windows\syswow64\odbcad32.exe. I'm not quite sure how the system decides which one to use from the admin tools, so I just navigate to the files and run them directly. )
So, the overview:
DxDesigner >> DxDatabook >> configuration.dbc >> ODBC connection >> database
The scripting method is simpler:
Script >> connection object >> connection string >> database.
With scripting, you have to know the structure of the database. There is nothing to tell you the table names, column names, or field data types. So you can easily break the database or get faulty data if you don't use it the way the database was designed. Fortunately, the database needed for dxdb is simple, without any complex relationships between tables, or anything of the sort. Each table is independent of the others, so once you know the table and column names, it's very straightforward.