The mm mysql jdbc driver has a last_insert_id() method to call after an
insert. It's the only way the driver returns you that info. What I
don't know though is how "accurate" it is? I think you can shoot
yourself in the foot if the call to it is not properly encapsulated within
a thread-safe/synchronized context. I'd hate for a call to
last_insert_id() to return a different id (someone else's insert that just
so happened between my insert and the call to last_insert_id()).
Therefore I think encapsulating this within a sync method and having an
action invoke it (like someone else on this group mentioned) may be the way
to go on this.
thanks,
Theron
Struts
Newsgroup To: [EMAIL PROTECTED]
<struts@baseb cc:
eans.com> Subject: Re: Hi Folks, 2 questions about
Actions and their
instance
04/01/02
10:40 AM
Please
respond to
Struts Users
Mailing List
Subject: Re: Hi Folks, 2 questions about Actions and their instance
From: Vic Cekvenich <[EMAIL PROTECTED]>
===
Imeditely calling is not good enough. You must use a JDBC driver
specific call that returns the last "affected rows" ID.
This gives you the new PK.
Vic
[EMAIL PROTECTED] wrote:
>>>There are 2 different path elements but both refer to the same Action
>>>
> class
>
>>>instance... Does this mean 2 static instances of
>>>BillingActionPreloadForm will exist or will only just 1 exist between
>>>
> the 2
>
>>>different action mappings that link to the same class?
>>>
>
>>I don't know, but it doesn't matter. You should always assume that
>>any specific instance of an Action class could potentially serve multiple
>>threads at once. Or else what's the point of putting your app on the
>>web? ;-)
>>
>
> Reason I brought this up is that I plan to use mysql. Mysql has those
> AUTO INCREMENT fields and I want to insert a record and immediately call
> last_index_id() to get the newly inserted row. If I do this is just
one
> and only one action, I may be able to prevent a timing/race condition by
> which last_index_id() may accidentally be returned from the wrong insert.
> I definitely want to prevent that from happening.
>
> thanks,
> Theron
>
>
>
>
> Jim Crossley
> <jcrossley@if To: Struts Users Mailing
List
> leet.com> <[EMAIL PROTECTED]>
> cc:
> 04/01/02 Subject: Re: Hi Folks, 2
questions about Actions and their
> 09:02 AM instance
> Please
> respond to
> Struts Users
> Mailing List
>
>
>
>
>
> [EMAIL PROTECTED] writes:
>
> [...]
>
>
>>So here's my 2 question(s):
>>
>>1. I then assume that "perform()" is synchronized
>>
>
> No. If all data objects are local to the perform method, there's no
> reason for it to be synchronized. If the data objects referred to in
> perform are shared, then their access should probably be synchronized,
> but not necessarily.
>
>
>>2. What about those cases where 2 different action mappings resort to
>>
> the
>
>>same action class?
>>
>
> [...]
>
>
>>There are 2 different path elements but both refer to the same Action
>>
> class
>
>>instance... Does this mean 2 static instances of
>>BillingActionPreloadForm will exist or will only just 1 exist between the
>>
> 2
>
>>different action mappings that link to the same class?
>>
>
> I don't know, but it doesn't matter. You should always assume that
> any specific instance of an Action class could potentially serve multiple
> threads at once. Or else what's the point of putting your app on the
> web? ;-)
>
> -- Jim
>
> --
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