Structure Packages

Use

A structure package bundles a set of packages at the top level of the package hierarchy. Structure packages do not contain any repository objects except for its own package interfaces and subpackages. Instead, they hold several main packages and are used to structure software projects. You can also use structure packages to specify the conditions for decoupling software components. Thus, they have a special significance as far as defining the basic architecture of SAP ERP is concerned. Examples of structure packages include BASIS, ABA, HR, and APPL.

Characteristics

Structure packages define the top node of a package hierarchy (above the main package level)
Structure packages contain only other packages, not development objects
Their package interfaces are used to specify the relationships between structure packages, not to add development objects.
In contrast to main packages and standard development packages, you can define filter package interfaces, default package interfaces and virtual default interfaces for structure packages.
You can bundle several structure packages in a surrounding structure package, which means that all SAP packages could be bundled together in one structure package (SAP).