Chapter 3 Building Physical Diagrams

Defining physical options for a PDM

A physical option is a parameter that defines how an object is optimized or stored in a database. Physical options can be included at the end of a Create statement and are DBMS-specific.

There are two types of physical options:

Default physical options for all the objects in the model (see "Defining default physical options")
Physical options for a specific object, which override the default physical option values (see "Defining physical options for individual objects")

Physical options are not supported for certain databases, and vary between databases. In ASA 6, for example, you can define physical options for tables, columns, indexes, tablespaces, and databases. Depending on the selected DBMS, options for keys, storages, and sequences may also be available.

DBMS syntax

The syntax for a physical option depends on the DBMS. The following is an example of a syntactical difference for the tablespace option in different DBMS:

DBMS	Tablespace option syntax
Oracle 6.0 or higher	Tablespace
Sybase Adaptive Server Anywhere	In

Changing DBMS

When you change DBMS, the physical option settings are applied as far as possible to the new DBMS. If a specific physical option was selected in the model, the default value is preserved for the option in the new DBMS. Unselected physical options are reset with the new DBMS default values.