Rational Developer for System z, Version 7.6

-DH lines in a Database block

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.

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 the directories of your workspace 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 ou click on a description line. In this section, you can enter information to complete the description line.

The -GG Lines section is used to provide the physical information necessary in order to generate the Block. It is associated with each description line. This section consists of a table in which you can modify the information contained in the Block Description lines before they are generated. Depending on the type of description line, the System automatically displays lines, in order to guide you when you enter the Block's physical information. These lines are identified by 'VIRT' or 'GUID' in the last field of the table. Collectively, these lines are called 'virtual' lines. The lines identified by '*VIRT' are generated. You can create new lines and override the 'virtual' lines generated by the DBD function if you want to modify them. A 'G' entered in the TYPE OF LINE field means that the lines are to be taken into account at generation time.

In the table you find the following input fields:
Type
When you click this field, a dropdown list allows you to select a line-type. You can choose between:
  • * : comment lines to be generated,
  • V: lines generated before the automatically generated elements.
  • G: line generated instead of the automatically generated elements.
  • P: lines generated between the element automatically generated parts and its description
  • Z: lines generated after the automatically generated elements.
    Note: P and Z types are available only for -GG lines associated with the CODASYL Blocks' definition and -DC lines.
Description
This field must be used to enter the generation elements or comments you want to be generated. Its content depends on the type of Block and type of line selected.

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