Lie Hetland book: Beginning Python..

[Steve Holden]

Gerhard Häring wrote:
> Vittorio wrote:
> 
>>[...]
>>Nonetheless, I was unable to find any documentation about such a 
>>different behaviour between Pysqlite and Pysqlite2; from my beginner 
>>point of view the Pysqlite (Magnus' version) paramstyle looks a better 
>>and more pythonic choice and I don't grasp the Pysqlite2 developers' 
>>intentions deviating from that way.
> 
> 
> The reason why pysqlite 0.x/1.x used paramstyle "pyformat", based on 
> Python string substitution for SQL parameters is that at the time 
> pysqlite was started, SQLite 2.x did not have any support for parameter 
> binding. So we had to "fake" it in Python, just like the MySQL interface 
> does (for the same reasons).
> 
> Later SQLite 2.x versions and of course SQLite 3.x supported real bound 
> parameters and pysqlite2 was developed from scratch to benefit from 
> them. SQLite 3.x supports both qmark and named paramstyles, so you can 
> use question marks *or* named parameters:
> 
>  >>> from pysqlite2 import dbapi2 as sqlite
>  >>> con = sqlite.connect(":memory:")
>  >>> cur = con.cursor()
>  >>> cur.execute("select 2*?", (14,))
>  >>> cur.fetchone()
> (28,)
>  >>>
>  >>> cur.execute("select 2 * :x", {"x": 14})
>  >>> cur.fetchone()
> (28,)
>  >>>
>  >>> x = 14
>  >>> cur.execute("select 2 * :x", locals())
>  >>> cur.fetchone()
> (28,)
>  >>>
> 
> I've also once written a wrapper using pysqlite 2.x's hooks that allows 
[...]
> 
>>I would be very grateful if someone would cast a light over 
>>Pysqlite/Pysqlite2 discrepancies.
> 
> 
> I think about the only place I wrote a bit about the differences was in 
> the pysqlite 2.0 final announcement:
> 
> http://lists.initd.org/pipermail/pysqlite/2005-May/000043.html
> 
Unfortunately this appears to mean that pysqlite2 isn't fully DB 
API-conformant.

 >>> import pysqlite2
 >>> pysqlite2.paramstyle
Traceback (most recent call last):
   File "<stdin>", line 1, in ?
AttributeError: 'module' object has no attribute 'paramstyle'
 >>>

Of course, given the module's flexibility it's difficult to know what 
you *would* put in paramstyle. I take it mixing different paramstyles in 
the same query will fail?

regards
  Steve
-- 
Steve Holden       +44 150 684 7255  +1 800 494 3119
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