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 development objects. 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 the 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 addition to main packages and normal packages, you can also define filter package interfaces for structure packages.
You can bundle several structure packages in a surrounding structure package, which means that all SAP packages can be bundled together in one package (SAP).