What locking method involves checking if a CDT is already being edited when a user begins editing it?

The relationship between data editing and locking mechanisms is crucial in applications like Appian. Pessimistic locking is the method that involves checking whether a complex data type (CDT) is currently being edited by another user before allowing a user to begin editing it. This is particularly important in scenarios where data integrity must be maintained and where concurrent edits could lead to conflicts or inconsistent data.

With pessimistic locking, when a user attempts to edit a CDT, the system checks for existing locks on that data. If another user is already editing the same CDT, the system prevents the current user from editing, thereby ensuring that only one user can make changes at a time. This approach minimizes the risk of data corruption or loss and enforces a strict control over data editing.

In contrast, optimistic locking, on the other hand, allows multiple users to edit the same data simultaneously and only checks for conflicts at the point of saving. This method assumes that conflicts are rare. Meanwhile, concurrent locking is not a standard term used in data management and does not accurately describe a locking method known in Appian or other systems. Thus, the correct identification of pessimistic locking reflects an understanding of its purpose in managing data integrity during edits.