[SqueakDBX] Character encoding and pooling in SqueakDBX and Glorp

Mariano Martinez Peck marianopeck at gmail.com
Thu Aug 26 19:43:12 UTC 2010

On Wed, Aug 25, 2010 at 7:20 AM, Panu Suominen
<panu.j.m.suominen at gmail.com>wrote:

> 2010/8/24 Mariano Martinez Peck <marianopeck at gmail.com>:
> > Yes. So that I can see it. Do you know if it breaks compatibility with
> other
> > databases or OS? because SqueakDBX classes like DBXConnection should be
> > cross-backend.
> I don't know how cross-platform my fix is. Database part should be
> fine. Postgresql can now detect the encoding.

Thanks a lot for the changeset. Now I will test with different OS and
databases and I will let you know.

now a couple of questions:

- I guess a lot of people doesn't need UTF (or other) encoding. And I guess
that the transformation brings some overhead in the query result mosty...(I
should run the benchmarks and see if there is difference). But I was
thinking if we could make this optional. I like the code and design you did.
I think that a good idea would be to add some kind of NullEncoder which is
set in:

DBXConnection >> initialize

instead of TextConverter newForEncoding: #utf8.

Then, for postgres, you will be using the one from  TextConverter
newForEncoding:  (r rows first valueAt: 1).

Even more, I would like to make it optional. Maybe we can create
DBXCOnnection class >> platform: aPlatform settings: aConnectionSettings
encode: anEncoder
and that will do:

platform: aPlatform settings: aConnectionSettings encoder: anEncoder
    ^self new
        platform: aPlatform;
        settings: aConnectionSettings;
        encoder: anEncoder;

Finally, the  cleint code (your app code) creates the connection with that
message :)

or something like that....but the idea of making it optional not to have
overhead if not required, and being able to be enabled from the app code.

- What happens is the database supports and specific encoding that Pharo
doesn't support?
 TextConverter newForEncoding:  (r rows first valueAt: 1).

will return nil, causing UndefinedObject dnu something.

maybe we can just set again the NullEncoder in that case?  or raise an error
?  what do you think?

Others database platforms just don't know anything about encoding
> (they use default utf-8). If other smalltalk dialects have
> TextConverter then it should be fine.
> If they haven't then I can implement another abstraction layer to
> provide compatibility between dialects.
> > If you want to can use another new package with your commit.
> I am sorry, but I did not quite understand what you meant...
> Unfortunately I am a little busy at work right now so I did not had
> time to learn how to use monticello properly to create version only
> containing required changes.
> For this reason I attached change set file to this mail.

Don't worry :)


> >> Also is there a connection pooling facility for SqueakDBX or Glorp?
> > Yes, several.
> Thank you.
> --
> Panu
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