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From Vadim Grinshpun <va...@ll.mit.edu>
Subject Re: flexible queries?
Date Wed, 28 Jun 2006 21:18:36 GMT
For this simple case, a stored proc might work, but if I understand your 
suggestion, it would involve enumerating the possible cases and using 
different queries.
However, the example I used was trivial, useful only for asking the 
question. What I actually need to do is a bit more complex.
Suppose you have a larger query, with multiple parameters that might or 
might not be present, and so there are a lot of possible combinations 
which would result in many different queries being generated. It'd be a 
pain to enumerate them all. Would a store proc really help in that 
situation? (I admit I'm fairly ignorant when it comes to stored procs, 
but it seems you'd have to be able to generate the SQL on the fly, which 
I doubt they can do).

Yee, Richard K CTR DMDC wrote:
> You should do this inside a stored procedure instead of using iBATIS or your
> code to do it.
> -Richard
> -----Original Message-----
> From: Vadim Grinshpun [mailto:vadim@ll.mit.edu] 
> Sent: Wednesday, June 28, 2006 11:58 AM
> To: user-java@ibatis.apache.org
> Subject: flexible queries?
> Hi everyone,
> Suppose I have a query where I want a join to be performed only if *one 
> or more* of a set of parameters are present.
> Is there a way in SqlMaps to do something like this? (below is an 
> example snippet of  what I'd like to do, using some pseudocode in the 
> first <dynamic> section):
>     table_foo f, table_bar b
>    <dynamic> <!-- if any of the params in the conditional are defined, 
> add one more table to join -->
>       <if>
>         <or>
>           <isEqual property="X.defined" compareValue="true" >
>           <isEqual property="X.defined" compareValue="true"  >
>         </or>
>        <then>, table_baz z</then>
>       </if>
>    </dynamic>
>    WHERE f.field = b.field
>    <dynamic>
>      <isEqual property="X.defined" compareValue="true" prepend="AND" 
>  >z.x_field > #X.value#</isEqual>
>      <isEqual property="Y.defined" compareValue="true" prepend="AND" 
>  >z.y_field = #Y.value#</isEqual>
>   </dynamic>
> Thanks,
> --Vadim

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