Use the CURRENT–VALUE statement to explicitly set a sequence to a new value. You can assign the defined initial value of a sequence, its upper or lower limit, or any integer value in between. Trying to set a value outside these bounds causes an error. Note that you cannot assign the Unknown value (?) to a sequence. Unlike the NEXT–VALUE function, the CURRENT–VALUE statement always sets a new sequence value in a transaction, starting one, if necessary.
Caution: Avoid using this statement in mission-critical applications. Use of this statement, especially in a multi-user context, can compromise the referential integrity of your database. Any database application designed to rely on the orderly values provided by sequences cannot reliably reset existing database fields according to potentially unexpected sequence values.
The purpose of the CURRENT–VALUE statement is to maintain a database off-line, under program control. Note that the Data Dictionary uses this statement when you create a new sequence to set the initial value. Possible uses include:
Restarting a terminating sequence that has terminated
Otherwise, resetting a sequence value for a specific test condition
Keep in mind that all such uses must respect and might require changes to the _Sequence table. This table contains one record for each sequence defined in the database. Creating a record in this table automatically allocates and assigns the data storage for a new sequence. Deleting a record in this table automatically releases the data storage for the specified sequence.
OpenEdge provides fault detection that prevents a sequence from being created with inconsistent attribute values in the _Sequence table (such as, the minimum value greater than the maximum value). It also prevents the assignment of a new current value that is inconsistent with the corresponding attribute values in the _Sequence table (such as, a current value outside the minimum and maximum value boundary).
The following code fragment sets a new current value for sequence used for testing:
DEFINE VARIABLE SeqValue AS INTEGER NO-UNDO.
DO TRANSACTION ON ERROR UNDO, RETRY:
SET SeqValue LABEL "TEST-Stepper Start" WITH SIDE-LABELS.
CURRENT-VALUE(TEST-Stepper) = SeqValue.
END. /* TRANSACTION */
. . .
OpenEdge also uses this statement in the Data Administration tool to load sequence definitions and values from dump-formatted text files. You can accomplish the same task implemented in the code fragment above using this tool. For more information, see OpenEdge Data Management: Database Administration.
Restarting a terminating sequence that has terminated