[jifty-devel] Clauses are AND'd by default in the limit method?

[Ruslan Zakirov]

On 12/5/06, Jesse Vincent <jesse at bestpractical.com> wrote:
>
>
>
> On Tue, Dec 05, 2006 at 04:01:04PM +0800, Agent Zhang wrote:
> > Hi,
> >
> > The Jifty::Manual::Models document contains the following snippet:
> >
> >    # combining restrictions with "AND"
> >    # note that "AND" is implicit here
> >    $collection->limit(column=>'col1', value=>'...');
> >    $collection->limit(column=>'col2', value=>'...');
> >
> > While testing my Qooqle app in Jifty, however, I found "OR" is
> > implicit here instead. By further examining the source of
> > Jifty::DBI::Collection, I've seen the following lines:
>
>
> Here's the way it works:
>
>
> * Toplevel clauses default to AND
> * Subclauses default to OR (though at one point, they defaulted to
>   whatever made sense. You can make decent guesses about what the user
>   means...except that you're often wrong);
> * By default, each column gets its own subclauses.
>
> So:
>
>
> $collection->limit(column =>  'col1', value => 'x');
> $collection->limit(column =>  'col1', value => 'y');
>
>         Will generate :
>
>         WHERE ( col1 = 'x' OR col2 = 'y');
          WHERE ( col1 = 'x' AND col2 = 'y');

>
>
> $collection->limit(column =>  'col1', value => 'x');
> $collection->limit(column =>  'col2', value => 'y');
>
>         Will generate:
>
>         WHERE ( col1 = 'x' ) AND  ( col2 = 'y');
>
> $collection->limit(column =>  'col1', value => 'x');
> $collection->limit(column =>  'col2', value => 'x');
> $collection->limit(column =>  'col2', value => 'y');
>
>         Will generate:
>
>         WHERE ( col1 = 'x' ) AND  ( col2 = 'x' OR col2 = 'y');
>
>
>
> You can get tricky by playing with the entry aggregator yourself:
>
> $collection->limit(column =>  'col1', value => 'x');
> $collection->limit(column =>  'col2', value => 'x', entry_aggregator => 'AND');
> $collection->limit(column =>  'col2', value => 'y', entry_aggregator => 'AND');
>
>         Will generate:
>
>         WHERE ( col1 = 'x' ) AND  ( col2 = 'x' OR col2 = 'y');
          WHERE ( col1 = 'x' ) AND  ( col2 = 'x' AND col2 = 'y');

>
>
> When you need to mix and match columns yourself, you can use an explicit 'subclause'
> $collection->limit(subclause => 'myclause', column =>  'col1', value => 'x', entry_aggregator => 'OR');
> $collection->limit(subclause => 'myclause', column =>  'col2', value => 'y', entry_aggregator => 'OR');
>
>         Will generate:
>
>         WHERE ( col1 = 'x' OR col2 = 'y');
>
> Does that help? Are you up for adding it to the docs? Thanks!
>
>
> > sub limit {
> >    my $self = shift;
> >    my %args = (
> >        table            => $self->table,
> >        column           => undef,
> >        value            => undef,
> >        alias            => undef,
> >        quote_value      => 1,
> >        entry_aggregator => 'or',
> >        case_sensitive   => undef,
> >        operator         => '=',
> >        subclause        => undef,
> >        leftjoin         => undef,
> >        @_    # get the real argumentlist
> >    );
> >    ....
> >
> > Apparently entry_aggregator defaults to "OR" according to the
> > implementation.
> >
> > Then which one is incorrect? The implementation or the documentation?
> >
> > Thanks,
> > Agent
> > _______________________________________________
> > jifty-devel mailing list
> > jifty-devel at lists.jifty.org
> > http://lists.jifty.org/cgi-bin/mailman/listinfo/jifty-devel
> >
>
> --
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-- 
Best regards, Ruslan.