Re: SINSERT Key Generator

Hello Anthony,

Thanks for your reply, I did a thorough test with about 50,000 records
of data under a multi-threaded environment and it worked well and data
integrity was maintained.

I will have a look at the how best we can be able to push this
implementation to the SDriver class and will discuss my ideas with you
in the coming days.

Kind regards.

Abel

On 5/4/11, anthony berglas <[email protected]> wrote:
> Actually,
>
> http://dev.mysql.com/doc/refman/5.0/en/information-functions.html#function_last-insert-id
>
> Says it is threadsafe.  Plus has a few caveats.  Thanks Tim.
>
> Anthony
>
> On Wed, May 4, 2011 at 1:01 PM, anthony berglas <[email protected]> wrote:
>
>> Hello Abel,
>>
>> Sorry for the late reply, but your code looks basically OK.
>>
>> However, it would probably be better to use the new standard
>> JDBC getGeneratedKeys() method.  If that works for MySql and HSQL then it
>> could be pushed up into SDriver for all databases
>> that supportsInsertKeyGeneration().  If you would like to do that that
>> would
>> be great.  See
>>
>>
>> http://dev.mysql.com/doc/refman/4.1/en/connector-j-usagenotes-basic.html#connector-j-examples-autoincrement-getgeneratedkeys
>>
>> I am suspicious of  the thread safety of LAST_INSERT_ID() (which
>> getGeneratedKeys probably uses beneath the covers).  To test, just set up
>> two manual  command lines sessions to a MySql database, Check AutoCommit
>> is
>> Off, insert a row in one session, then in the second session, then go back
>> to the first session and Select Last_Insert_Id.  It is important that it
>> be
>> the first record, not the second.
>>
>> This would be a valuable contribution to SimpleOrm.  If you get it working
>> just with MySql, we can push it up for you.
>>
>> You make a good point about the references.  Children assume parents
>> already have their keys.  I suppose there should be a lazy way to get
>> them.
>>  But for now just flush.
>>
>> Regards,
>>
>> Anthony
>>
>> On Wed, Apr 27, 2011 at 12:55 PM, Anthony & Melissa Berglas <
>> [email protected]> wrote:
>>
>>>
>>>
>>> ---------- Forwarded message ----------
>>> From: Abel Birya <[email protected]>
>>> Date: Mon, Apr 18, 2011 at 3:50 PM
>>> Subject: [SimpleORM] SINSERT Key Generator [1 Attachment]
>>> To: [email protected]
>>>
>>>
>>>
>>>
>>> [Attachment(s)<#12fb8f45faf831e3_12f94e2668a4f8ce_12f67290b26e68e3_TopText>from
>>> Abel Birya included below]
>>>
>>> Hi,
>>>
>>> I was wondering whether anyone has been able to do an implementation of
>>> this key generator mode for MySQL. I implemented the methods
>>> supportsInsertKeyGeneration() & retrieveInsertKey() of the
>>> SDriverMySQL.java
>>> class and so far I am able to retrieve my inserted key from the db when a
>>> commit() is done.
>>>
>>> One thing that I have noticed though is that in the event that an entity
>>> represents a foreign key in another table, I have to explicitly call the
>>> session.flush() method in order for the entity to bear its primary key
>>> field
>>> value before I call the setReference() method in the child record.
>>>
>>> I was wondering whether there is anyone who has time to assist me in
>>> testing this. I am currently working on a project that needs to work in a
>>> multi-threaded environment where there will be many connections to the DB
>>> at
>>> once and I wanted to find out how effective the retrieveInsertKey()
>>> method
>>> is going to be in such an environment and whether I will be able to
>>> maintain
>>> data integrity all across the different threads that are running.
>>>
>>> I have attached the SDriverMySQL.java class.
>>>
>>> Kind regards.
>>>
>>> Abel
>>>
>>>
>>>
>>>
>>>
>>> --
>>>
>>> *Spreadsheet Detective,
>>> *Southern Cross Software Queensland Pty Limited
>>> 54 Gerler Street, Bardon, Queensland 4065, Australia.
>>> www.SpreadsheetDetective.com
>>>  <http://www.spreadsheetdetective.com/>*"If the model seems correct only
>>> because the numbers look right,
>>> then why build the model in the first place?"
>>> *
>>>
>>>
>>
>>
>> --
>>
>> Dr Anthony Berglas, [email protected]       Mobile: +61 4 4838 8874
>> Just because it is possible to push twigs along the ground with ones nose
>> does not necessarily mean that that is the best way to collect firewood.
>>
>>
>
>
> --
>
> Dr Anthony Berglas, [email protected]       Mobile: +61 4 4838 8874
> Just because it is possible to push twigs along the ground with ones nose
> does not necessarily mean that that is the best way to collect firewood.
>


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