Re: JDBC Transactions - Mailing list pgsql-general

From Jonathan Tripathy
Subject Re: JDBC Transactions
Date
Msg-id 4CCF0939.5000006@abpni.co.uk
Whole thread Raw
In response to Re: JDBC Transactions  (Filip Rembiałkowski <filip.rembialkowski@gmail.com>)
Responses Re: JDBC Transactions  (Jonathan Tripathy <jonnyt@abpni.co.uk>)
Re: JDBC Transactions  (Andy Colson <andy@squeakycode.net>)
List pgsql-general
>> 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.
>> 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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