Rational Developer for System z, Version 7.6

Lignes -DH dans un bloc base de données

In the -DH lines tab, you can describe the relationships between Segments in a hierarchical database (example: DL/1).

Each line designates a Segment and its parent (except for the line referring to the root segment). The description consists on records which make up the physical file.

This description is common to the following Block types:
  • HIERARCHICAL DATABASES - IMS/DL1:
    • 'DP': Physical Database Description.
    • 'DR': Physical Database Description (same as 'DP', but only the data elements referenced as access keys in the segment description are generated in the 'FIELD......' statements).
    • 'DL': Logical Database Description.
    • 'PC': PCB. '.
    • IP': Primary Index
    • 'IS': Secondary Index.

-DH lines definition

The -DH lines definition section displays when you enter ou click on a description line. In this section, you can enter information on the description line.

Definition
The PCB or PSB code field is active only for PC or PS-type Blocks. To select a PCB or PSB database block, you must click on Change, a dialog box opens. You find a list where you can select instances of PCB and PSB databases available in your connexion repositories. If you want to create a new database block instance, click the New database block in the bottom of the dialog box. The code of the selected database displays as a link that switches you to the Database block's editor.
For a PCB or PSB database called on a -DH line, you have only the Key indicator or option field and Comment/relationship/key length to be completed.

The following Segment options are active for all Block types other than the PC or PS-type.

Segments
Select here the Segment code. SOCRATE/CLIO database: Select the code of the Segment which is used to generate the entity, the formal or the SOCRAT/CLIO Segment. To enter or modify the contents of this field, click Change. In the dialog box that opens, you can choose a Segment code in the list of Segments available in your repositories or create a new Segment.
Parent Segment
Click Change to select the code of the Segment upon which the given Segment is hierarchically dependent. This field is not used for IP or IS-type Database Blocks.
For SOCRATE/CLIO database: select the code of the SOCRATE/CLIO entity on which the Segment is defined.
Relation code
This field is optional. You can indicate the code of the Model Relationship corresponding to the DL/1 Relationship. The System automatically creates the cross-references of the Model Relationship to DL/1 Relationships.
Key indicator or Option
Enter in this field the key indicator used for a symbolic reference of the key Data element of a given Segment in a given Database Block. The character indicated in this field must also be entered in the -CE lines of the Segment, in the Sort key field of Data Element call line.
In this field, you can enter:
  • U to indicate a unique key,
  • M to indicate a multiple key
  • a digit between 1 and 9 to indicate a DL/1 Secondary index,
  • $ in a PCB or a physical or logical DBD, if you want to generate a non-qualified SSA,
  • any other values to indicate a search field.
Note: Key indicators are not permitted on a Data Elements that are used to redefine other Data Elements.
Estimated number of links
You enter here the average number of occurrences of a child Segment linked to one occurrence of its parent Segment.
SOCRATE/CLIO database: enter here the number of occurrences of an entity. By default, the occurrence specified on the Definition of the entity.
Comment/Relationship/Key length
This field can be used to document the defined parent/child link. It is also used to indicate the concatenated key length.
When generating PS-type Database Blocks, i.e. a PSB, the system automatically calculates the length of the longest concatenated key. This is done for:
  • Each DBD called in a PSB,
  • Each PCB called in a PSB,
  • Each INDEX Database called as an independent database in the PSB.
This length may be overridden by entering the following input on the first line: CC=n (with n = 9 to 9999).
On each segment call line, you may enter PR=nnnn, used to generate the parameter PROCOPT=nnnn at the SENSEG statement level when generating the PSB containing this DBD, PCB, or INDEX Database.
Note: This calculation is done only for a primary Segment. In the case of a secondary index, the CC= parameter is required.

-GG Lines

The -GG lines section displays when you enter or click on a description line. In this section, you can enter information to complete the description line.


Conditions d'utilisation | Commentaires en retour

Ce centre de documentation utilise la technologie Eclipse. (http://www.eclipse.org)