This tab enables you to describe the relationships between
Segments in a hierarchical database (example: DL/1). It is also used
to describe a SOCRATE/CLIO database.
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.
- SOCRATE/CLIO DATABASES:
- 'SA': Add of SOCRATE structure.
- 'SO': SOCRATE structure.
- 'SS': SOCRATE sub-structure.
-DH lines
The -DH lines definition section displays when you enter ou click on a description line.
In this section, you can enter information for the selected description
line.
-DH lines definition
- 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 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 line, the system automatically generates virtual documentation
lines associated with the description line. These lines can be modified
or deleted.
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:
- a Blank-type line to create a comment which will
not be generated,
- a *-type line to create a comment which will
be generated,
- a G-type line to add generation elements on the
Block's description,
- a V-type line for the generation, from a Segment,
a customized SQL access with no delimiters.
- Description
- This field must be used to enter the genartion elements or comments.
Its content depends on the type of line selected.
- PHYSICAL DBD:
The virtual lines associated with a description
line of a physical DBD retrieve the Segment descriptions as defined
in the Repository. They do not need to be rewritten. A
FIELD description can be modified at this level. To
do so, insert line(s) between the beginning and the end of the insertion
area, indicated on virtual lines. On the first line, enter the Data
Element code corresponding to the
FIELD to be modified, left-justified between
< and
> signs. You must enter six characters
between the delimiters or complete with blanks. Enter the new description
of
FIELD on the following lines.
Example: G <DELCO >
G FIELD NAME=(NUM,SEQ,U),BYTES=7,...
- LOGICAL DBD
The virtual lines associated with a description
line of a logical DBD retrieve, for each Segment of the DBD, the name
of the Segment and the name of the parent Segment. You must complete
each line by identifying the source of the Segment.
SOURCE = ((name of segment,,name of DBD))
- INDEX
The virtual lines associated with the Index database block
description line retrieve the Segment description from the Repository.
VA Pac does not have the necessary information for the description
of a given Index (LCHILD, etc.). Therefore, you must complete the
virtual lines.
- PCB
No virtual lines are associated with a PCB Database Block.
You can modify a PCB description through the virtual lines associated
with the description lines of a PSB using this PCB.
- PSB
The virtual lines associated with PSB description lines
retrieve the Segment description(s) making up the called PCB from
the Repository. They do not need to be rewritten. A
SENSEG description can be modified at this level.
To do so, insert line(s) between the beginning and the end of the
insertion area, indicated on virtual lines. On the first line, enter
the Segment code corresponding to the
SENSEG to be modified, left-justified between
< and
> signs. You must enter four characters
between the delimiters or complete with blanks. Enter the new description
of
SENSEG on the following lines.
Example: G <CD10>
G SENSEG NAME=CLCDE,PARENT=COCRD,PROCOPT=G