Re: [sqlite] Detach says database is locked

[Jim Wilcoxson]

This type of thing works with SQLite 3.6.18.  I have a similar issue with
3.7.  I believe the difference is that in 3.6.18, if you do a select on a
main database that doesn't involve an attached database, the attached
database isn't locked.  In 3.7, if you do a select on the main database that
doesn't involve an attached database, but there IS an attached database, the
attached database is locked anyway.  Then it's not possible to detach it
with the open select, even though that select has nothing to do with the
attached db.

I don't know if this new behavior is a bug in 3.7, or is considered a fix to
3.6.

Jim
--
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On Thu, Oct 21, 2010 at 12:21 PM, Alan Chandler
wrote:

> On 21/10/10 00:35, Igor Tandetnik wrote:
> > Alan Chandler  wrote:
> >> Further to my other post related to attaching to databases with PHP PDO,
> >>   I have now managed to ATTACH OK
> >>
> >> However, when I come to DETACH, I am getting a Database is locked error
> >> when I try and execute it.
> >>
> >> The only thing happening to that database in between ATTACH and DETACH
> >> is a single row SELECT
> >
> > Make sure you reset or finalize the statement (not sure how it's done in
> PHP).
> I believe closeCursor();  does the job.  If not, I unset the variable.
>
> However, I have figured out the problem - which is really sad since I
> can't do what I hoped - which is loop round a set of rows from a higher
> level select statement ATTACHing and DETACHing to a database in turn .
> Because the top level select loop is its own transaction, you can't
> detach from the database which you attached in the inner part of the
> loop since at that moment you are in a transaction.
>
> I think my way out of the problem is to pull out all the rows into a
> single array, then close the transaction and interate over the array
> members.  Fortunately in the case its just a menu - so there probably
> won't be too many items.
>
>
>
> --
> Alan Chandler
> http://www.chandlerfamily.org.uk
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Re: [sqlite] Detach says database is locked

[Alan Chandler]

On 21/10/10 00:35, Igor Tandetnik wrote:
> Alan Chandler  wrote:
>> Further to my other post related to attaching to databases with PHP PDO,
>>   I have now managed to ATTACH OK
>>
>> However, when I come to DETACH, I am getting a Database is locked error
>> when I try and execute it.
>>
>> The only thing happening to that database in between ATTACH and DETACH
>> is a single row SELECT
>
> Make sure you reset or finalize the statement (not sure how it's done in PHP).
I believe closeCursor();  does the job.  If not, I unset the variable.

However, I have figured out the problem - which is really sad since I 
can't do what I hoped - which is loop round a set of rows from a higher 
level select statement ATTACHing and DETACHing to a database in turn . 
Because the top level select loop is its own transaction, you can't 
detach from the database which you attached in the inner part of the 
loop since at that moment you are in a transaction.

I think my way out of the problem is to pull out all the rows into a 
single array, then close the transaction and interate over the array 
members.  Fortunately in the case its just a menu - so there probably 
won't be too many items.



-- 
Alan Chandler
http://www.chandlerfamily.org.uk
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Re: [sqlite] Detach says database is locked

[Simon Slavin]

On 21 Oct 2010, at 12:27am, Alan Chandler wrote:

> The only thing happening to that database in between ATTACH and DETACH 
> is a single row SELECT

If you try it without the SELECT does it work ?

Does the SELECT return any results ?

Simon.
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Re: [sqlite] Detach says database is locked

[Igor Tandetnik]

Alan Chandler  wrote:
> Further to my other post related to attaching to databases with PHP PDO,
>  I have now managed to ATTACH OK
> 
> However, when I come to DETACH, I am getting a Database is locked error
> when I try and execute it.
> 
> The only thing happening to that database in between ATTACH and DETACH
> is a single row SELECT

Make sure you reset or finalize the statement (not sure how it's done in PHP).
-- 
Igor Tandetnik


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[sqlite] Detach says database is locked

[Alan Chandler]

Further to my other post related to attaching to databases with PHP PDO, 
  I have now managed to ATTACH OK

However, when I come to DETACH, I am getting a Database is locked error 
when I try and execute it.

The only thing happening to that database in between ATTACH and DETACH 
is a single row SELECT

I don't really understand why I can't DETACH.  Can anyone give me any 
ideas what this could be.
-- 
Alan Chandler
http://www.chandlerfamily.org.uk
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