Record Locking

I need some edification on how Oracle handles record locking.

Can you get a read-lock if a write-lock exists on a record and vice-versa.
- can a write lock be obtained after a read lock has been set?

• If so, will the read view be refreshed?
• can dirty reads be done for queries & reports while a write lock is set?

Thanks for the help.

-- 
BTW, please respond via email as well as this newsgroup, since I don't get
a change to check the newsgroups too often.  Thanks.

Rich Beynon
The Stratus Group, Inc.
E-Mail: rbeynon_at_stratusgroup.com
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