Because a bitmap index is an Oracle specific feature that can only be done in the Physical Model for Oracle RDBMS.

You define the indexes in Relational Model. First go to Table Properties of the table you want to create an index for and press the green plus. Add the information needed.

Then in Physical Model (for Oracle RDBMS) select that index and define it as bitmap index.

When generating the DDL, you will get something like this:

CREATE BITMAP INDEX Orders_Customer_CustNO_IDX ON Orders
(
Customer_CustNO ASC
)
LOGGING ;

Note: If you want ALL your indexes in Oracle RDBMS to be bitmap indexes, you can define a template for indexes and set bitmap as a default. First enable the defaults for Oracle Physical Models Index Templates in Preferences:

Then set (Press View/Edit) the default for Bitmap Index as YES.

I have defined Primary Key, Unique Key and Foreign Key Constraints and I know I want to have indexes for them. Do I really need to go and define them one by one in Data Modeler? Not necessarily.

Go to Design Properties (double-click the name of the design or right-click and select Properties). Enable all or those you want from Automatic Index Generation.

Now when you generate the DDLs, the DDLs for generating these indexes will be generated automatically.

How are those automatically generated indexes called? You can define that also in Design Properties as the template for Automatic Index.

I have designed the Logical Model, pressed the double-arrow (Engineer to Relational Model) to get the Relational Model. Now I am ready to create a Physical Model for that Relational Model but how to do it?

In Browser, under your Relational Model, select Physical Models.

Right-click and select New.

Then select the RDBMS and the version you want for a Physical Model (in Data Modeler terminology it is the Database Site).

That’s it. You now have the Physical Model for the Relational Model. Note that you can have several Relational Models for one Logical Model and several Physical Models for one Relational Model, if needed.

NOTE: The Physical Model is not opened automatically when you open a design (for performance reasons). Go to the same Physical Models, right-click and select Open.