Deadlocks: What locks are obtained for an update

Hi all,

I'm currently investigating a deadlock & I'm not understanding why my update statement on table x is holding an exclusive lock on table y.

I'm guessing it is because table x has a foreign key to table y, and because the applications data access layer updates every column in table x whenever an update occurs i.e. while the foreign key column of table x does not need to be updated, it is, because it appears that's the way the app performs all updates!

Before I request this to be changed - I want to make sure my guess is correct. If someone could please confirm/correct:

1. a. An update statement on table x can take exclusivelocks on any tables referenced by table x

b. If a foreign key column is not included in the update statement, the update statement will not take any lock on the referenced table

Thanks for reading.

Clay.