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Logical Databases

What is a Logical Database

A logical database is a DBD definition that references structures already defined in one or more physical databases (physical DBDs). Such a definition is known as a logical DBD.

To an application, a logical DBD always appears as a single hierarchical physical DBD. However, a logical DBD is derived from the relationships (especially the logical relationships) defined in the associated physical DBDs.

Logical Databases Provide Flexibility

Logical databases provide flexibility for applications by allowing them to view the same physical data in many different ways. It is important to remember that each logical DBD is still hierarchical in nature for all of the DL/I calls that use it.