record locks

[Ian Devaney]

In practical terms, why would I want to lock records with a read lock 
or a write lock?

I've never really "got" it!

Ian

On 28 May 2004, at 1:45 pm, valentina-request at lists.macserve.net wrote:

> Message: 9
> Date: Fri, 28 May 2004 14:11:35 +0300
> From: Ruslan Zasukhin <sunshine at public.kherson.ua>
> Subject: Re: record locks
> To: <mergault.olivier at wanadoo.fr>, <valentina at lists.macserve.net>
> Message-ID: <BCDCF917.1C232%sunshine at public.kherson.ua>
> Content-Type: text/plain; charset="ISO-8859-1"
>
> On 5/28/04 12:55 PM, "mergault.olivier at wanadoo.fr"
> <mergault.olivier at wanadoo.fr> wrote:
>
>> Name:      Mergault Olivier
>>
>> Question regarding: v4rb
>>
>> V4RB Reference pdf is not very helpfull to understand how records are 
>> locked
>> and
> &#160;unlocked !Espacially for beginners !
>>
>> So, how can one learn all about that essential point ?
>
> Hi Mergault,
>
> This is true that Valentina 1.x docs are short, and often require 
> expert
> level from developer. We try improve this in 2.0 docs.
>
> You can read about record locks in ANY SQL book, I believe.
>
> Actually all easy.
>
> No locks -- no problems. No locks.
>
> Read Lock. Or shared lock.
>     You can set it if record do not have WRITE lock,
>     several users can set READ lock on the same record.
>
> WRITE LOCK,
>     you can set it if record do not have any other locks.
>
>
> Cursor when is created, locks all selected records as you have specify.
>
> If it cannot lock at least one record as required, then ALL fails, and 
> you
> get error Cannot set lock.
>
> When cursor die, it unlock all records.
>
>
> -- 
> Best regards,
> Ruslan Zasukhin      [ I feel the need...the need for speed ]
> -------------------------------------------------------------
> e-mail: ruslan at paradigmasoft.com
> web: http://www.paradigmasoft.com
>
> To subscribe to the Valentina mail list go to:
> http://lists.macserve.net/mailman/listinfo/valentina
> -------------------------------------------------------------