1. Importing the physical schema saves you time and effort by importing the
structure for the physical layer. If you do not import the schema, you must create each table, primary key,
foreign key, and any other objects against which you want to generate queries.
2. When you import schema for most databases, the default is to import tables,
primary keys, and foreign keys.
NOTE: It is
recommended that you not import foreign keys from a database because the process
is lengthy when importing a large number of tables.
3.When you import physical tables, be careful to limit the import to only those tables that contain data that are likely to be used in the business models you create. You can use a filter (table mask) to limit the number of tables that appear in the import list. This makes it easier to locate and select the tables that you want to import.
4 .You can also import database views, aliases, synonyms, and system tables. But import these objects only if you want the Oracle BI Server to generate queries against them.
5. Importing large numbers of extraneous tables and other objects adds unnecessary
complexity and increases the size of the repository.