Runtime Considerations › Application Components and Physical Data Sets

Application Components and Physical Data Sets

The relationship between application components and physical data sets begins with IDD file entities and ends with the description of the files in the JCL or data set labels.

IDD File Entities

You define IDD file entities to represent the input and output files in the application. You do not define file entities for suspense and log files. Suspense files use the file entity descriptions of their associated input files. Log files are not described in the data dictionary.

A single file entity can represent several files, as long as the characteristics included in the file entity are common to all files that the entity represents. For example, you do not have to specify any characteristics as part of the file entity; therefore, you can define one file entity to represent all files in an application.

More information on specifying file characteristics is provided earlier in this chapter.

IDD Record Entities

You define record entities that describe the layout of data for all input and output files in an application. You must associate each record entity with the appropriate file entity; if you are using the IDD DDDL compiler, you do this by specifying the INCLUDE WITHIN FILE clause of the RECORD statement.

Defining File Maps

You define file maps that associate file record entities with dialog variable storage.

Defining Dialogs

You define dialogs that associate file maps with the application.

Described below are some different combinations you can use when associating maps with dialogs in an application:

• You can associate a map with several dialogs.
• You can specify that a map is one dialog's input map and is the same or another dialog's output map.
• In an application that accesses a file with multiple record layouts, you define a map for each layout and associate each map with its own dialog.

You can associate a dialog with one input map, one output map, or both. You assign a suspense file to a dialog that is associated with an input file by specifying the runtime label (z/OS ddname, z/VSE filename) of the suspense file either during dialog definition or in a runtime control statement.

Note that IDD elements in records used by an CA ADS Batch application should not specify an external picture that includes P (for numeric data).

Runtime Labels

Runtime labels (z/OS ddname, z/VSE filename) associate file maps and suspense files with physical data sets. You specify runtime labels during dialog definition or in runtime control statements. Specifications made in control statements supersede those made during dialog definition.

You can specify the same runtime label for different file maps. For example, in an application that accesses a file with multiple record layouts, you define a file map for each record layout. During dialog definition or at runtime, you specify the same runtime label for each file map.

You can specify different runtime labels for the same file map. For example, in an application that reads records from one file and writes them to another, you can define a single file map for both files, since they have the same record layout. You associate the file map with one dialog as its input file map, and specify the runtime label of the input file. You associate the file map with the same dialog or another dialog as its output file map, and specify the runtime label of the output file.

Data Sets

You describe the application's physical data sets in the JCL and identify the data sets to the application by means of runtime labels.