Because stores tend to have thousands of articles, assigning layout modules and assortments to stores and creating listing conditions for them can be very computer resource intensive. Furthermore, updating store layout modules individually can be needlessly laborious. However, especially if you have stores with similar but not identical assortments, you can significantly streamline this process using delta modules.

A delta module is a kind of "exception" module. When you create a delta module for a layout module version, it serves to add and/or remove specific articles. Delta modules cannot stand alone -- they must always belong to a layout module version. You might think of delta modules as "modifiers" for layout modules. They are typically assigned to those sites which have the fewest differences from the standard assortment.

You create delta modules in the SAP Retail Space Management Interface. In the posting BAPI, you can specify that they be assigned to one or more specific sites. You can create several delta modules for a layout module version (the version indicating a time frame for which the layout module is valid), but can only assign one delta module to a site. So, for example, you can create delta module 1 for layout module A, version 0000, and delta module 2 for layout module A, version 0000. But you cannot assign both delta modules 1 and 2 to site A.

You can only create delta modules by using the SAP Space Management Interface.