Oracle Forms Developer – Form Builder Reference, Volume 1

SYSTEM.COORDINATION_OPERATION system variable
Syntax
SYSTEM.COORDINATION_OPERATION
Description
This system variable works with its companion SYSTEM.MASTER_BLOCK to help an On-Clear-
Details trigger determine what type of coordination-causing operation fired the trigger, and on which
master block of a master/detail relation.
The values of the two system variables remain constant throughout the clearing phase of any block
synchronization. SYSTEM.MASTER_BLOCK represents the name of the driving master block, and
SYSTEM.COORDINATION_OPERATION represents the coordination-causing event that occurred on
the master block.
The Clear_All_Master_Details procedure, which is automatically generated when a relation is created,
checks the value of SYSTEM.COORDINATION_OPERATION to provide special handling for the
CLEAR_RECORD and SYNCHRONIZE events, which may be different from the handling for other
coordination-causing events. The Clear_All_Master_Details procedure also checks the value of
SYSTEM.MASTER_BLOCK , to verify that while it is processing the master block of a relation
coordination, it is searching only for blocks containing changes.
For example, given the relation hierarchy between blocks shown below, moving to the next record using
the [Next Record] key or the Record, Next menu command while in Block C would cause blocks E, F, G,
and H to be cleared (and perhaps subsequently queried, depending on the Deferred_Coordination
property of the CE and the CF relations).
When the On-Clear-Details trigger fires for block C, the result is:
:System.Cooordination_Operation = ’NEXT_RECORD’
:System.Master_Block = ’C’
The Clear_All_Master_Details procedure will clear all of block C’s details, causing a "chain reaction" of
Clear_Block operations. Consequently, block F is cleared.
Since F is a master for both G and H, and it is being cleared, an On-Clear-Details trigger will fire for
block F as well. However, since the clearing of block F was driven (indirectly) by a coordination-causing
event in block C, these remain the values in the On-Clear-Details trigger for block F:
:System.Cooordination_Operation = ’NEXT_RECORD’
:System.Master_Block = ’C’
Note: The values of these two system variables are well-defined only in the scope of an On-Clear-
Details trigger, or any program unit called by that trigger. Outside this narrow context, the values of
these two variables are undefined and should not be used.
The possible values of SYSTEM.COORDINATION_OPERATION, when it is appropriate to check that
variable, are described in the following table.
Value Description Caused By
MOUSE Mouse to non-current record Mouse
UP Move up a record Menu, key, PL/SQL
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