Besides using versioning, what methods can be used to implement optimistic locking in a system?

Optimistic locking can be implemented not only through versioning but also by other methods:

• Using timestamps: when reading data, the time of the last update is saved. When saving, it is checked that the time has not changed.

• Compare-and-swap: before updating, it is checked that the data has not changed since reading, by comparing the old and current state.

• Using hash sums or checksums: when reading, a hash of the data is calculated; when writing, it is checked that the hash has not changed.

• Using special flags or state markers: for example, a field with a flag that changes upon update and is checked before writing.

All these methods allow detecting conflicts without explicit resource locking, which increases performance in systems with low contention.