DB structure when replacing XE in place of Three Access Databases.

Question

We have an application which has three access databases for offline access. For online access we use Oracle 10g. Now we want to replace these three access databases with XE. the three offline dbs are for the use of keeping some downlaoded data, transaction data and reporting data. Two of the Access databases have same schema and same tables. How do i replicate similar structure with XE as there is a limitation that we can not create more than 1 database. Please suggest.

Answer 1

The concept of a 'database' is different.
You can have three separate schemas in a single XE database. A schema belongs to a user.
If we call your three Access databases, TOM, DICK and HARRY, we create three users in XE called TOM, DICK and HARRY.
We migrate the Access TOM to the XE TOM, and so on.
In XE, TOM can have a table called ORDERS, and so can DICK and HARRY.
If TOM is logged in, he will see TOM's ORDERS table, HARRY will see HARRY's and DICK will see DICK's.
If we have another user (eg SUE), you would GRANT privileges on TOM's tables to SUE.
SUE can select from TOM.ORDERS. You could also add grants to SUE from HARRY and/or DICK, and SUE can select from DICK.ORDERS.
You can create a SYNONYM in SUE called ORDERS to point to TOM's ORDERS table, or (more flexibly) issue an ALTER SESSION SET CURRENT_SCHEMA=TOM so that any reference that SUE makes to ORDERS are interpreted as referring to TOM.ORDERS.