Re: [GNUe-dev] New condition-element available to Appserver

[Johannes Vetter]

Hi,

thanks for reminding me about the prefix-notation i've forgotten before:
it looks like this:

['exist', 'table(=class)', 'masterlink', 'detaillink', [subcondition]]


Thanks,
Johannes

Am Dienstag, den 25.01.2005, 15:11 +0100 schrieb address@hidden:
> hi,
> 
> what would be the correct syntax for a session.find()?
> 
> is it:
> 
> ['exist', 'class', 'master', 'detail', [subcondition...]]
> 
> or:
> 
> ['exist', ['table', 'class'], ['masterlink', 'master'], ['detaillink',
> 'detail'], [subcondition...]]
> 
> thanks,
> 
> malek
> 
> 
> Quoting Johannes Vetter <address@hidden>:
> 
> > Hi,
> > 
> > We've introduced a new condition-element 'exist'. It's main purpose is
> > to perform a sub-select and to return False if that sub-select was empty
> > or True if it was not empty.
> > 
> > Example: Invoicing
> > 
> > I want to see all customers that have an order for item 'FOO'.
> > 
> > 
> > Here comes the XML-Syntax of the new condition-element:
> > 
> > <datasource name="dtsFoo" ...>
> >  <condition>
> >  ...
> >  <exist table="detailtable" masterlink="f,f,..." detaillink="f,f,...">
> >   <condition>...</condition>
> >  </exist>
> >  ...
> >  </condition>
> > </datasource>
> > 
> > 'table' defines the table to be queried by the sub-select.
> > 'masterlink' specifies the fields to be compared from the current
> > datasource (i.e. 'dtsFoo')
> > 'detaillink' specifies the fields in 'table', which must match with the
> > fields in 'masterlink'. Note: the order and number of items must be the
> > same.
> > 
> > An optional 'sub-condition' could be added. If it is given, this
> > condition will be used as condition for the subselect.
> > 
> > 
> > Example:
> > 
> > (To see the structures used for this example, please have a look at
> > gnue-appserver/samples/testing/joins/struct.gcd)
> > 
> > 
> > <datasource name="dtsCust" connection="appserver" table="test_customer">
> >     <condition>
> >       <exist table="test_lineitem" masterlink="gnue_id"
> >              detaillink="test_invoice.test_customer">
> >         <eq>
> >           <cfield name="test_item.test_code" />
> >           <cconst value="G1" />
> >         </eq>
> >       </exist>
> >     </condition>
> >   </datasource>
> > 
> > 
> > The above definition would select all rows from 'test_customer', which
> > have a result in: all rows from test_lineitem, where
> > test_invoice.test_customer matches the former row in 'test_customer'
> > *and* where 'test_item.test_code' is equal to 'G1'.
> > 
> > 
> > 
> > Thanks,
> > 
> > Johannes
> > 
> > 
> > 
> > -- 
> > BYTEWISE Software GmbH          Tel +43 (5577) 89877-0
> > i.A. Johannes Vetter            Fax +43 (5577) 89877-66
> > A-6890 Lustenau, Enga 2         http://www.bytewise.at
> > -------------------------------------------------------
> > Wir bieten die Installation von Debian GNU/Linux auf
> > Servern für kleinere Netzwerke zum Pauschalpreis an.
> > Mehr dazu unter http://www.bytewise.at/texte/pl-debian
> > 
> > 
> 
> 
> 
> 
> _______________________________________________
> Gnue-dev mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/gnue-dev