DataServer.RLockVerify Method |  |
Determine if the current record in this data server has any pending updates and lock it for exclusive write access if there are none.
Namespace: VO
Assembly: VOSystemClasses (in VOSystemClasses.dll) Version: 2.21
SyntaxRequest Example
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TRUE if the record is unchanged and the lock was successfully taken; otherwise, FALSE.
Return Value
Type: UsualTRUE if the record is unchanged and the lock was successfully taken; otherwise, FALSE.
Remarks
This method checks for pending updates to the current record by comparing the values that were read to the record when the server was initially positioned on the record with the current values in the corresponding database record.
If the values match, it signifies that no other user has modified the data since the user started working on it, and, therefore, that it is safe to lock the record and let the user continue with an update transaction. (Note that when locked, other users can still make read-only reference to the record.)
If the values do not match, somebody else has changed the record, and the user should refresh the values from disk and restart the transaction. The application has to decide what to do about values that are different. Note that DataServer:Status can be used to determine the reason for the failure.
This method is used for optimistic concurrency control. See "Concurrency Control" in the Programmer's Guide for more information.)
See Also