The Zim object definition commands (e.g., CREATE, ERASE, RENAME) operate against a single object at a time. For example, an EntitySet is created using a CREATE command. If you needed to create all of the EntitySets, you need to issue a series of these commands.

ZOM, on the other hand, operates on sets of objects. ZOM enables you to select a set of objects from among the universe of objects in your application and apply an operation against that set of objects. For example, recreating all EntitySets is as simple as executing the command:

ZOMReCreate +t Ent

The “+t Ent” syntax is an example of the powerful selection criteria available for retrieving objects. In this case, “+t Ent” indicates that the Type of the object must be EntitySet. As you read in the following subsections, there are many other selection criteria, as well as operations for combining sets of objects in various ways.