Hi @TanyaS58

By default, when the parent case is locked, the child case inherits the lock, as indicated in the `pyworkpage.pxlockhandle`. This means that if the parent is locked, access to the child case is also restricted, and vice versa, resulting in a single lock instance stored in the `pr_sys_locks` table. This behavior is managed by the out-of-the-box activity `DetermineLockString (set pxLockHandle with either the work object's pzInsKey or its cover's key if cover key is present and  lock the parent option)`. 

When selecting "Allow one user" for the parent case, Pega Platform automatically locks the parent when any user opens a child case. To enable a second user to modify the parent case simultaneously, you can check the "Allow other users to access parent case when the child case is opened" option.

Please let me know if you need further clarifications.

Thanks,

Ravoof.

@TanyaS58

Yes, it is possible to make the parent case locking as default and provide optimistic locking to the child case. By overriding the locking strategy of a child Case, users can update the parent Case even if the child Case is open, allowing for optimistic locking. Additionally, you can define a lock duration for a child Case that is shorter than a lock duration for a parent Case, providing more flexibility in managing concurrent updates.