Hello,
Booleano and Geniusql seem to be two different things:
* If you need to *parse* a text-based filter (aka "boolean expression"), use
Booleano.
* If you already have the data in a useful form (i.e., no need to parse
anything), use Geniusql.
BTW, you can use a Booleano parse tree not only to create an SQL `WHERE`
clause, but also to create a SQLAlchemy filter, for example -- you can turn
these trees into anything you need (or at least that's the goal).
Cheers,
- Gustavo.
Robert said:
> Heck, if all you want is the back end, Geniusql (and therefore Dejavu)
allows you to build comparison expressions and combine them with "+", "&", and
"|":
> >>> from geniusql import logic
> >>> a = logic.comparison('Name', 6, ['Dave', 'Jerry', 'Sue'])
> >>> a
>
> logic.Expression(lambda x: x.Name in ['Dave', 'Jerry', 'Sue'])
>
> >>> b = logic.comparison('Size', 2, 30)
> >>> b
>
> logic.Expression(lambda x: x.Size == 30)
>
> >>> a + b
>
> logic.Expression(lambda x: (x.Name in ['Dave', 'Jerry', 'Sue']) and
> (x.Size == 30))
>
> >>> a & b
>
> logic.Expression(lambda x: (x.Name in ['Dave', 'Jerry', 'Sue']) and
> (x.Size == 30))
>
> >>> a | b
>
> logic.Expression(lambda x: (x.Name in ['Dave', 'Jerry', 'Sue']) or (x.Size
> == 30))
>
> >>> c = logic.Expression(lambda g, h: g.Name == h.Name)
> >>> c
>
> logic.Expression(lambda g, h: g.Name == h.Name)
>
> >>> a + c
>
> logic.Expression(lambda x, h: (x.Name in ['Dave', 'Jerry', 'Sue']) and
> (x.Name == h.Name))
>
> You then pass those to the storage layer where they are automatically
> converted to backend-specific SQL etc. Been runnin' like a champ for years,
> not days. [1]
>
>
> Robert Brewer
> fuman...@aminus.org
>
> [1] OK, I did have to commit a patch just now for comparison() in
> py2.5+--but it's a short one ;)
> http://www.aminus.net/geniusql/changeset/280
--
Gustavo Narea <xri://=Gustavo>.
| Tech blog: =Gustavo/(+blog)/tech ~ About me: =Gustavo/about |
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