- The DESCRIPTION command defines the structures/layouts of source and target datastores and is used in conjunction with the DATASTORE command to associate a data structure/layout with a physical datastore.
- DESCRIPTION commands must be specified prior to any DATASTORE commands that reference fields within a DESCRIPTION structure/layout.
- It is common for a DESCRIPTION to be used by more than one DATASTORE (such as when the source and target record layouts are the same).
- Record or segment layouts are normally defined by metadata in files which are external to the script.
| Metadata type | <description_type> | Used for |
|---|---|---|
| SQL DDL (data definition language) | SQLDDL | Relational database tables |
| COBOL Copybook | COBOL |
VSAM, IMS*, mainframe file |
|
DBD (database definition) |
IMSDBD | IMS* |
| C header file | CSTRUCT |
Binary data (in a file or messaging system) |
| PL1 | PL1 |
Mainframe file |
| XML DTD (document type definition) | XMLDTD | XML data |
Syntax
DESCRIPTION <description_type> |COBOL|CSTRUCT|IMSDBD|DB2SQL|ORASQL|MSSQL|SQLDDL|XMLDTD|PL1
<file_name> | /+in line syntactically correct description on as many lines as required+/
AS <description_alias
[KEY IS <key1> [,<key2>...,<keyn>]]
[FOR SEGMENT <segment_name> IN DATABASE <dbname>]
[TOPIC <topic>]
[SUBJECT <subject>]