File > External Data has two options that you want to consider: Import and
Link Tables. Import is easier to explain, and to contrast against, so I will
explain that first.
If you use import, you will be able to make a duplicate copy of the tables
you select. For instance, if DB1 imports the table Contacts from DB2, both
DB1 and DB2 will have their own separate copies of the table Contacts. If
you add a contact to DB1, it will not be added to DB2, and vice versa.
Linking tables helps to eliminate the problem of multiple databases needing
the same data. If DB1 creates a link to the Contacts table in DB2, no data
is duplicated and we do not have the import problem. Any changes you make to
Contacts in DB1 will be reflected in DB2, and vice versa. DB1 will be able
to use the Contacts table as if it were it's own.
However, there is a limit. A very minor restriction, but a restriction none
the less. You can add/remove/edit the data in the tabe until the end of the
world, but in order to change the design of the table you will need to access
it through DB2.
Hope that helps!
Nick
