Sqlite

Marcelo Barbero marcelobarbero en arnet.com.ar
Mar Ene 30 05:05:32 CET 2007


Sin embargo, más adelante dice (ver lo que encierro entre ***):

We are aware of no other embedded SQL database engine that supports as much
concurrancy as SQLite. SQLite allows multiple processes to have the database
file open at once, and for multiple processes to read the database at once.
*** When any process wants to write, it must lock the entire database file
for the duration of its update. But that normally only takes a few
milliseconds. Other processes just wait on the writer to finish then
continue about their business. *** Other embedded SQL database engines
typically only allow a single process to connect to the database at once.

However, client/server database engines (such as PostgreSQL, MySQL, or
Oracle) usually support a higher level of concurrency and allow multiple
processes to be writing to the same database at the same time. This is
possible in a client/server database because there is always a single
well-controlled server process available to coordinate access. If your
application has a need for a lot of concurrency, then you should consider
using a client/server database. *** But experience suggests that most
applications need much less concurrency than their designers imagine. ***

When SQLite tries to access a file that is locked by another process, the
default behavior is to return SQLITE_BUSY. You can adjust this behavior from
C code using the sqlite3_busy_handler() or sqlite3_busy_timeout() API
functions. 

Entiendo mal el inglés?

Marcelo

-----Mensaje original-----
De: python-es-bounces en aditel.org [mailto:python-es-bounces en aditel.org] En
nombre de NeCuDeCo
Enviado el: Lunes 29 de Enero de 2007 08:43 p.m.
Para: La lista de python en castellano
Asunto: Re: [Python-es] Sqlite

"Multiple processes can have the same database open at the same time.
Multiple processes can be doing a SELECT at the same time. But only one
process can be making changes to the database at any moment in time,
however."

http://www.sqlite.org/faq.html#q7

Hombre, que no lo permite :P

On 1/29/07, Marcelo Barbero <marcelobarbero en arnet.com.ar> wrote:
>
> Cómo que no lo permite?
>
> Bueno, si nos ponemos exquisitos, puede ser que no sea así, pero con 
> el volumen de "terminales" (4 PDAs!!!) no creo que tengas problemas de 
> concurrencia, ya que Sqlite lo va a resolver rápidamente.
>
> Marcelo
>
> -----Mensaje original-----
> De: python-es-bounces en aditel.org [mailto:python-es-bounces en aditel.org] 
> En nombre de NeCuDeCo Enviado el: Lunes 29 de Enero de 2007 04:49 p.m.
> Para: La lista de python en castellano
> Asunto: Re: [Python-es] Sqlite
>
> No lo permite.
>
> prueba db4o.
>
> On 1/29/07, Ekaitz Lizundia <elizundia en fitbak.com> wrote:
> >
> > Saludos a todos,
> >
> > ¿ Alguien sabe si Sqlite permite multiples accesos a la vez para 
> > escribir en una misma base de datos ?
> >
> > Yo tengo una BD donde desde 4 PDAs diferentes van a escribir a la 
> > vez en esa BD. Y seria con Sqlite.
> >
> >
> > --
> > Ekaitz Lizundia Huete
> > Fitbak SL
> > Telf. 943 367098
> >
> > elizundia en fitbak.com
> > _______________________________________________
> > Python-es mailing list
> > Python-es en aditel.org
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> >
>
>
>
> --
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--------------------------
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