Technical data

Subschema Section
2. The Subschema Section names the subschema you want to use. It describes
a logical view of the database as it is to be accessed by the COBOL program.
It begins with the Subschema Section header containing the reserved words
SUB-SCHEMA SECTION followed by a period ( . ) separator character.
3. The Subschema entry follows the Subschema Section header.
4. The Subschema entry consists of a level indicator (DB), a sub-schema-name,
the reserved word WITHIN, a schema-name, and an optional database clause.
5. A DB entry specifies the following:
• Which subschema contains the descriptions of the data to be made
available to the COBOL program
• Which schema contains the subschema definition in Oracle
CDD/Repository
• The name of the database that the program is to be run against
• The stream name
6. A run unit can declare only one Subschema (DB) entry.
7. Keeplist entries follow the Subschema (DB) entry. A keeplist is a table
containing an ordered list of database key values.
8. Each database key value represents a record occurrence in the Oracle
CODASYL DBMS database. A keeplist can contain the same database key
value any number of times. Any number of keeplists can contain the same
database key value any number of times.
9. A database key is added to the end of a keeplist by the KEEP or the FIND
ALL statement and selectively removed by the FREE statement. One FIND
ALL statement can add multiple database keys to a keeplist.
10. The number of entries in a keeplist is called the cardinality of the keeplist.
A keeplist with zero entries is called an empty keeplist. The order of the
entries in the keeplist reflects their sequence of insertion. As entries are
added, the cardinality of the keeplist increases. As entries are removed, the
cardinality decreases.
11. A COBOL program can reference a keeplist by using a database key identifier.
12. The Database Control System (DBCS) creates and maintains all keeplists.
13. No other run unit can update a record whose database key value is in a
keeplist. The DBCS locks each record that is in a keeplist. The record
remains locked until the program frees it or until the program executes a
COMMIT (without the RETAINING option) or ROLLBACK statement, or
until the program terminates.
File Section
Working-Storage Section
Linkage Section
Report Section
Screen Section (Alpha, I64)
The last five COBOL sections are described and discussed in the HP COBOL
Reference Manual chapter on Data Division.
Data Division 3–3