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From Eric Lazarus <ericllaza...@yahoo.com>
Subject Re: Query Examples Needed � Expression.fromString() syntax?
Date Wed, 24 May 2006 19:45:29 GMT
Thank you, Michael and Joshua! 

What about efficiency? If I want to "and" in a bunch
of things, like as many as 10 things if the user fills
in all the fields of the web query form, then it would
look like this? :

Expression e =
ExpressionFactory.greaterExp("estimatedPrice", new
BigDecimal(100000.0));

e = e.and( ExpressionFactory.lessExp("estimatedPrice",
new
BigDecimal(5000.0)) );

e = e.and( ExpressionFactory.lessExp("productSize",
BigDecimal(100.0) );

e = e.and( ExpressionFactory.lessExp("productWeight",
new
BigDecimal(200.0)) );

I can just keep appending conditions on like this?
Will this turn into efficient SQL code if done this
way? If not, what is the best way?

Thanks,

Eric

--- Joshua Pyle <joshua.t.pyle@gmail.com> wrote:

> I never use fromString any more.
> 
> But using the expressionFactory to and and or
> expressions is very simple...
> 
> Expression e =
> ExpressionFactory.greaterExp("estimatedPrice", new
> BigDecimal(100000.0));
> 
> e = e.and(
> ExpressionFactory.lessExp("estimatedPrice", new
> BigDecimal(5000.0)) );
> 
> -- 
> Joshua T. Pyle
> Go has always existed.
> 
> On 5/24/06, Eric Lazarus <ericllazarus@yahoo.com>
> wrote:
> > Would anyone reply with some nice examples of
> > SelectQuery beside the simple one here:
> >
> >
>
http://www.objectstyle.org/cayenne/userguide/dataobjects/dataobjects-example.html
> >
> > Expression e =
> >   ExpressionFactory.greaterExp("estimatedPrice",
> >                         new BigDecimal(100000.0))
> >
> > I need to do things with ANDS and ORs and I'm not
> sure
> > how to use expression factory (or should I use
> > Expression.fromString() ?) to do it.
> >
> > Right now my immediate need is to be able to
> construct
> > a query with an arbitary number of possible "and"
> > clauses depending on what the user types.
> >
> > Seems like fromString() is going to be easy and
> > powerful but I can't find an example of the syntax
> > using google.
> >
> > Even just a few nice examples would be helpful.
> >
> > Can I look at the attributes of sub objects using
> this
> > syntax? How?
> >
> > Thanks!
> >
> > Eric
> >
> >
> > __________________________________________________
> > Do You Yahoo!?
> > Tired of spam?  Yahoo! Mail has the best spam
> protection around
> > http://mail.yahoo.com
> >
> 
> 
> -- 
> Joshua T. Pyle
> Go has always existed.
> 


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