You define the description lines of a Database Block in a tab that is specific to each
Database Block type. The -DH Lines tab is specific to the hierarchical
Database Blocks. The -DR Lines tab is specific to the relational Database
Blocks. The -DC Lines tab is specific to the CODASYL, DMSII, and TANDEM
Database Blocks.
About this task
The various description lines are used for specific purposes:
- The -DC lines are used to logically describe a CODASYL schema or subschema: declare areas, call
records and distribute them among areas, define, and describe sets (code, name, owner record, member
record).
- The -DH lines are used to describe the relationships between Segments in a hierarchical database
(example: DL/1).
- The -DR lines are used to specify the SQL objects that constitute a relational database (table
spaces, tables, table views, index, or key).
In the tab that is dedicated to the description lines of a Block, you specify the description
lines of the current Block in a table. You can also delete or reorganize lines. The other part of
the tab displays a definition section that opens when you select a description line in the table. In
this section, you can give further information about the selected description line. Moreover, you
can access the
-GG Lines by clicking
-G Lines and
specify the generation elements that are associated with the selected description line.
Procedure
- To create a -DC line, click Add -DC line or select this action in the
contextual menu. A default set line (
S) is created in the table. You can change the line type or complete the new line directly
in the table or in the -DC line definition section. You can create generation
elements (-GG lines) for the description line by clicking -G Lines and using
the available templates.
- To create a -DH line, click Add -DH line or select this action in the
contextual menu. A default -DH line (
) is created in the table. You can complete the new line directly in the table or in the
-DH line definition section. You can create generation elements (-GG lines)
for the description line by clicking -G Lines.
- In the -DR Lines tab, you can create a -DR line that contains
information such as the object type, external name, and corresponding Segment name. You can also
create a -K line that represents the key type that is supported by the Segment and the generation
code.
- To create a -DR line, click Add -DR line or select this action in the
contextual menu. A default table space line (
P) is created in the table. You can change the line type or complete the new line directly
in the table or in the -DR line definition section. You can create generation
elements (-GG lines) for the description line by clicking -G Lines and using
the available templates.
- To create a -K line, select a line that describes an SQL record whose type is index, alter
table or primary key and click Add -DR—K line. A default key line (
) line is created in the table, nested under the SQL record line. You can specify the
composition of the Segment that represents the SQL record directly in the table or in the
-K line definition section.