On 01/11/10 18:38, Jonathan Tripathy wrote:
Hi Andy,
Thanks for your reply. Would the above code be classed as a single
transaction then?
Yes, assuming there's no explicit transaction control
(COMMIT/ROLLBACK/END) in your queries.
Actually, we do have maybe one or 2 queries that use ROLLBACK, however
ROLLBACK happens at the end of a "code block" so the question is
probably moot.
Please ignore this above comment from me. We are using JDBC's rollback()
method, instead of comitt() (in a catch block), so all seems fine.
And if so, I could just simple leave out the line which
says "//Insert SQL here to lock table"?
In PostgreSQL, locking is done automatically depending on actual
isolation level and SQL queries.
You can use explicit locking but most of the time it's not needed.
I'll give you the exact case where I'm worried:
We have a table of customers, and each customer can have multiple
memberships (which are stored in the memberships table). We want our
deleteMembership(int membershipID) method to remove the membership,
then check to see if there are no more memberships left for the
corresponding customer, and if there are none, delete the
corresponding customer as well.
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