Rational Programming Patterns

-CD Lines tab

The purpose of this tab is to identify the external resources of a Program. These resources are represented by Data Structures.

For each external resource, you must specify the following information:
  • Physical characteristics, which, along with the type of COBOL code, generate the SELECT clauses and ensure adequate physical accesses,
  • File matching criteria, controlled by three different fields (for input Data Structures):
    • sort key, which identifies the keys to match on, arranged in hierarchical order
    • number of control breaks, which specifies how many control breaks there are
    • synchronization level, which specifies the number of levels to match
  • The generated description type: Several description variants can be defined from the Data Structure descriptions contained in the Library. These variants are:
    • the format type used
    • the selection of certain Segments, taken from the various Data Structure descriptions in the Library
    • the selection of certain reserved Data Elements or groups of Data Elements
    • the record description mode (redefined or not, repeated, for example), and the COBOL level number
    • the location of the generated description in the DATA DIVISION (this location can vary from one record to another)
  • Use characteristics, which generate input/output processing, and other standard processing (check, update, printing, and so forth).
Data Structure calls are used to describe three basic types of elements, which are specified in the Organization field:
  • standard files,
  • Database Blocks,
  • work areas or linkage areas.

At the Program level, you can build a composite Data Structure, that is call different Data Structures on the same -CD line.

Limitations:

There is no limitation on the number of Data Structure calls per Program. However, principal Data Structures, or Data Structures with control breaks or file matching must be among the first 23. If not, file matching might not be carried correctly and these principal Data Structures are not updated.

For files whose organization is I: Indexed, V: VSAM, UFAS or S: Sequential, the number of call lines must not exceed 100.

The maximum number of times a single Data Structure can be called is limited to 500, for all the Programs that are generated in one run.

A called Segment can call another one. A maximum of 4 levels of nesting are possible.

Recommendation

In this tab, you can specify internal resources, which are work or linkage areas, represented by Data Structures or Data Elements. However, it is advised to declare them directly in the COBOL code, using micropatterns.

Description of the tab

It is constituted of three different parts:
  • An editable table, which is identical to the Pacbase -CD screen. You can enter values directly in this table, if you are familiar with the -CD screen. Double-clicking a line which calls an instance opens the instance editor.
    Note: For a guided input, you must use the definition sections, which you open with the Add... buttons. These sections only display the relevant fields for the inserted elements, with all the possible values for each field.
    Important: For explanations and the list of all the possible values for each input field, see the detailed help of the appropriate definition section. For example, to see the detailed explanations on OARFU, see the help of the -CD Line Definition (Data Structure) section.

    All the table columns are shown by default. To reduce the number of columns, right-click the table and select Show columns > Select.

    The table contains three embedded levels:
    • On the first level, the CD line, which represents the called resource: the Data Structure.
    • On the second level, the Data Structure which constitutes the -CD line.
    • On the third level, the selected Segments for each Data Structure. If no Segment has been specified, all the Segments of the Data Structure are selected by default and their codes are not shown here.
    The table columns represent the Data Structure call characteristics:
    • Category:
      • Input file (Input file icon),
      • Output file (Output file icon),
      • Input/output file (Input/Output file icon),
      • Working file (Working file icon),
      • Report line (Report line icon),
    • Definition:
      • Code in Program (Program column).
      • Code in the repository, which is the Data Structure name, entered upon creation in the creation wizard. If the Data Structure is composite, you can see the names of all the Data Structures which make up this -CD line. The first Data Structure displayed is the principal Data Structure.
      • External name (External column),
      • All the characteristics specified in the OARFU column: organization (O column), access mode (A column), recording mode (R column), input/output mode (F column), unit type (U column).
      • Usage, which triggers the generation of certain specific functions (table loading, validation, updating...) (U column).
    • Physical characteristics;
      • Block factor (spaces and zeros are equivalent) (column Block) and Block type (records or characters) (T column), accessed with the More button of the -CD Line Definition (Data Structure).
      • Physical unit type (Unit column) and its complementary column (C column), accessed with the More button of the -CD Line Definition (Data Structure).
      • Format type (F column ) for the Data Structures which are not to be printed.
      • File status (Stat File column), accessed with the More button of the -CD Line Definition (Data Structure). This field is optional.
    • File matching criteria, controlled by three different columns (for input Data Structures):
      • Number of control breaks (B column),
      • Synchronization level (M column),
      • Transaction control break level (first L column in the table). The corresponding field is accessed with the More button of the -CD Line Definition (Data Structure).
    • Information required for the correct generation of this Data Structure call:
      • Result Data Structure (RE column) and source Data Structure code (SE column), accessed with the More button of the -CD Line Definition (Data Structure).
      • Selection (Selection column), which contains the sort key composition. It is the sorting order of the Data Elements which constitute the sort key. The sort key is specified on the -CE Lines tab of Segments.
      • Generated description type (R column), in which you select the type of record description to be used in the COBOL program. The Segment description stored in the Library can then have different uses.
      • Reserved error codes in transaction files (column E), in which you indicate if optional Data Elements (ENPR, GRPR and ERUT) used as error vectors are to be generated.
      • COBOL record level (second L column in the table), used with the Generated description type, This level defines the COBOL level number for the descriptions of Data Structures, Segments and Data Elements.
      • COBOL position (Pl column), used to obtain a Data Structure description in a particular area.
    • The Data Structure access key (Access key column), required for indexed Data Structures and the record-type Data Element (RecType El column). The values of this Data Element identify the various record types of a Data Structure. The corresponding fields are accessed with the More button of the -CD Line Definition (Data Structure).
  • Buttons which you use to add Data Structures to your Programs, remove existing calls, or move them up/down.
    Note: The possible actions with the buttons are also available in the contextual menu of the table.
  • Sections which open up depending on your selection in the table or on the line you want to create. These sections contain fields in which you select or enter the values. When you save, these values are then displayed in the table.
    Important: For explanations and the list of all the possible values for each input field, see the detailed help of the appropriate definition section. For example, to see the detailed explanations on OARFU, see the help of the -CD Line Definition (Data Structure).

    If you select or create a:

    • -CD line, two cases are possible:
      • If the -CD line calls Data Structures (input file, working file...), the -CD Line Definition (Data Structure) opens up. You enter all the characteristics of the external resource in the Program in it.
        Note: Some of the values are entered in fields which can only be accessed with the More button of the -CD Line Definition (Data Structure).
      • If the -CD line calls Reports, the -CD Line Definition (Report) opens up.
    • Data Structure call, the Data Structure call opens up, that is its composition (where you select all or some of the Data Structure Segments). From there, you can access the Data Structure editor tabs.
    • Segment call, the Segment call opens up. You must indicate the Segment code in the Program and from where you can access the Segment editor tabs.
    • Report call, the Report call opens up. From there, you can call another Report, indicate its suffix in the Program or access the Report editor tabs.

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