The Microsoft Systems Management Server (SMS) API accesses objects in a site database by retrieving information about those objects and storing it in containers. After your application has populated a container with objects from a site database, the application can access those objects and their properties.
There are six different types of containers for objects: C_SITE, C_MACHINE, C_PACKAGE, C_JOB, C_MACHINEGROUP, and C_SITEGROUP. Structurally, the instance of an object within a container is represented as a folder.
Before your application populates a container, it can set filters on the container. Filters specify the objects to retrieve from the site database and store in the container. If no filter is set for a container, all objects (of the type supported by the container) are returned when the container is populated.