It is important to be able to predict the manner in which object selection interacts with your input from a command so that the objects you expect are selected for processing.
The object selection capability provides you with the option to select objects by data group, object selection parameter, or a combination. Object selection supports four classes of objects: files, objects, IFS objects, and DLOs.
The object selection process takes a candidate group of objects, subsets them as defined by a list of object selectors, and produces a list of objects to be processed. The below illustrates the process flow for object selection.
Figure 20. Object selection process flow
Candidate objects are those objects eligible for selection. They are input to the object selection process. Initially, candidate objects consist of all objects on the system. Based on the command, the set of candidate objects may be narrowed down to objects of a particular class (such as IFS objects).
The values specified on the command determine the object selectors used to further refine the list of candidate objects in the class. An object selector identifies an object or group of objects. Object selectors can come from the configuration information for a specified data group, from items specified in the object selector parameter, or both.
MIMIX processing for object selection consists of two distinct steps. Depending on what is specified on the command, one or both steps may occur.
The first major selection step is optional and is performed only if a data group definition is entered on the command. In that case, data group entries are the source for object selectors. Data group entries represent one of four classes of objects: files, library-based objects, IFS objects, and DLOs. Only those entries that correspond to the class associated with the command are used. The data group entries subset the list of candidate objects for the class to only those objects that are eligible for replication by the data group.
If the command specifies a data group and items on the object selection parameter, the data group entries are processed first to determine an intermediate set of candidate objects that are eligible for replication by the data group. That intermediate set is input to the second major selection step. The second step then uses the input specified on the object selection parameter to further subset the objects selected by the data group entries.
If no data group is specified on the data group definition parameter, the object selection parameter can be used independently to select from all objects on the system.
The second major object selection step subsets the candidate objects based on Object selectors from the command’s object selector parameter (file, object, IFS object, or DLO). Up to 300 object selectors may be specified on the parameter. If none are specified, the default is to select all candidate objects.
The selection parameter is separate and distinct from the data group configuration entries. If a data group is specified, the possible object selectors are 1 to N, where N is defined by the number of data group entries. The remaining candidate objects make up the resultant list of objects to be processed.
Each object selector consists of multiple object selector elements, which serve as filters on the object selector. The object selector elements vary by object class. Elements provide information about the object such as its name, an indicator of whether the objects should be included in or omitted from processing, and name mapping for dual-system and single-system environments. See Table 55 for a list of object selector elements by object class.