How is concurrency handled? What is optimistic concurrency vs pessimistic concurrency?

• Optimistic concurrency: Assumes that conflicts are rare. EF checks for changes

before saving using concurrency tokens.

• Pessimistic concurrency: Locks records in the DB to prevent other updates (not

supported out-of-the-box in EF Core).

EF Core supports optimistic concurrency using [ConcurrencyCheck] or

[Timestamp].