VCursor lock question - 2d try

[Joseph Morgan]

I am at a loss then. I don't have enough knowledge of vcursor yet to give a qualified answer to your question. 

Joseph

> On Oct 8, 2013, at 3:02 PM, François Van Lerberghe     <frvanlerberghe at gmail.com> wrote:
> 
> Hi Joseph,
> Thank you to your reply. Unfortunately, this doesn't solve my problem.
> 
> I have one cursor locked in RW mode (containing all records of one table)
> and next I need to make a second cursor to modify some records (50) of that
> table. As explained before I see 3 ways to do this. Witch one do you think
> it's better ?
> 
> François Van Lerberghe
> Rue Thier Monty, 15 A
> 4570 Marchin
> +32 (0)85 25 08 25
> 
> 
> le 8/10/13 18:44, Joseph Morgan <joseph at checkos.com> a écrit :
> 
>> I am not sure what to do in this situation. But I saw this on xojo forum and
>> maybe you can adapt their solution to your needs:
>> 
>> https://forum.xojo.com/5486-how-best-to-handle-updating-one-field-in-a-bunch-o
>> 
>> 
>> I hope this helps. :)
>> 
>> Joseph
>> 
>>> On Oct 8, 2013, at 11:38 AM, François Van Lerberghe
>>> <frvanlerberghe at gmail.com> wrote:
>>> 
>>> As nobody answer my question, let me post it again :
>>> 
>>> I have a function (RealBasic/Xojo method) where I update every record of a
>>> table (5000 records). In order to do that, I make a VCursor with
>>> EVLokType.kReadWrite on the whole table.
>>> At the end of this function , I call another function to update a few
>>> records (50) of that same table. This update is in another function because
>>> it is called by some other places of the project. How must I deal with the
>>> records locking in this second Vcusor using the same table, but not the same
>>> records ?
>>> 
>>> 1) If I nil the first Vcursor (locking the whole table) before create the
>>> second, locking the needed records, I have a risk (very low I know, but that
>>> exist) that, just before I create my second Vcursor, another user lock some
>>> records of that table, reading or writing incorrect data and stopping me to
>>> complete the work.
>>> 
>>> 2) Must I keep the first Vcursor ensuring that nobody can modify the table
>>> and create the second with kNoLock ? Is it safe to update the records in
>>> this second Vcursor ?
>>> 
>>> 3) I see a third option : Keeping the first cursor. I pass this Vcursor as
>>> parameter to iterate, test each record and update the records that meet some
>>> condition. I don't like this option as
>>> - I prefer sending a second SQL query to retrieve the needed records rather
>>> than iterate and test each record
>>> - this second function is called by some other places of the project
>>> 
>>> I prefer the second option if it is safe. Could you be kind enough to give
>>> me your advice on this ?
>>> 
>>> François Van Lerberghe
>>> Rue Thier Monty, 15 A
>>> 4570 Marchin
>>> Belgium
>>> 
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