Technical data

This statement removes the fifth-positioned database key value from KEEPLIST-
2. Removing a keeplist entry changes the position of all the following entries. For
example, after freeing entry 5, entry 6 becomes the fifth-positioned entry, entry 7
becomes the sixth-positioned entry, and so forth. The FREE statement changes
the ordinal position of a database key value in the keeplist, not its contents.
5.14.3 Transactions and Quiet Points
You generally segment your run unit into transactions, bounded instances of run-
unit activity. A transaction begins with the first DML statement in the run unit
or with a READY statement that follows a COMMIT or ROLLBACK statement;
continues through a series of DML data access statements; and ends with either a
COMMIT statement, a ROLLBACK statement, or the termination of the run unit.
Before the initial READY statement is issued, after the COMMIT or ROLLBACK,
and before the next READY, the run unit is at a quiet point. A quiet point is the
time that exists between the last executed COMMIT or ROLLBACK statement
and the next READY statement, or the time prior to the first executed READY
statement.
The Quiet Point—Transaction—Quiet Point continuum provides the DBCS with
a structure that allows it to control access to and ensure the integrity of your
data. To implement this control, the DBCS uses currency indicators and locking.
Figure 5–33 shows the segmentation of a run unit into transactions and quiet
points.
Figure 5–33 Transactions and Quiet Points
PROGRAM
BEGINS COMMIT**
PROGRAM
ENDSREADY*ROLLBACK***READY*COMMIT**READY*COMMIT**READY*
*Transaction begins
**Transaction ends and get committed
***Transaction ends and gets aborted
Quiet point Quiet point Quiet point Quiet point Quiet pointTransactionTransactionTransactionTransaction
ZK−1508−GE
5–34 Database Programming with HP COBOL