ibatis-user-java mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Pascal DeMilly <list.iba...@newgenesys.com>
Subject Re: java.util.HashMap as resultClass
Date Mon, 24 Jan 2005 18:48:48 GMT
Well. It seems logical to me. Why would iBatis go into great length at
trying to map result in the SqlMap file then if it was not to limit the
knowledge of your database to that XML file. The dependency have to stop
somewhere and it seems to me the SqlMap file is the place where it
should stop. The DAO implementation classes should only know about the
iBatis map id and its expected POJO results not how your database
columns are named or it seems to me.

Anyway, in my case while this solve one of my problem, queryForMap is
still not as efficient as it could be since it relies on queryForList.
So basically it is building two list. One with each element being a Map
of column name/value, then another map of only values. Would it be more
efficient to rewrite queryForMap to use a RowHandler?



On Mon, 2005-01-24 at 10:15, Brandon Goodin wrote:
> Why is it a problem to have a code dependency in an "implementation"
> class? It is suppossed to be aware of IBatis SQLMap semantics. You
> interface over your DAO class should hide the specifics of your
> implementation code within your Dao.
> 
> Brandon
> 
> 
> 
> 
> On Mon, 24 Jan 2005 09:22:49 -0800, Pascal DeMilly
> <list.ibatis@newgenesys.com> wrote:
> > Thanks Larry,
> > 
> > I tried it and it works. However this still leave some dependencies in
> > my DAO code as I have to specify the column names there as in:
> > 
> > return getSqlMapClientTemplate().queryForMap("getItemNameMap", null, "SKU", "Description");
> > 
> > How will you do about moving that code into the SqlMap. Should I create
> > a custom resultMap with key/value as properties and refer to it in my
> > DAO code?
> > 
> > I am going to give it a try and see what happened.
> > 
> > Thanks for you help.
> > 
> > Pascal
> > 
> > On Mon, 2005-01-24 at 08:44, Larry Meadors wrote:
> > > Try executeQueryForMap() instead.
> > >
> > >
> > > On Mon, 24 Jan 2005 08:42:25 -0800, Pascal DeMilly
> > > <list.ibatis@newgenesys.com> wrote:
> > > > Hi,
> > > >
> > > > I would like to retrieve a Map with whose key is the 1st column of my
> > > > query and the value is the 2nd column. For example right now I do:
> > > >
> > > > <select id="getItemNameMap" resultClass="java.util.HashMap">
> > > >         select SKU, Description from Items
> > > > </select>
> > > >
> > > > However this returns a list of maps with the key being the column name
> > > > and the value the column value which seems wasteful in term of space (I
> > > > am using remoting to retrieve that info).
> > > >
> > > > I currently solve it by using a custom rowHandler in my DAO as follow:
> > > >
> > > >     public Map getItemNames () throws DataAccessException {
> > > >         final KeyValueHandler rowHandler = new KeyValueHandler ();
> > > >         getSqlMapClientTemplate().queryWithRowHandler("getItemNameMap",
null, rowHandler);
> > > >         return rowHandler.getMap();
> > > >     }
> > > >
> > > >     private class KeyValueHandler implements RowHandler {
> > > >         final Map map = new HashMap ();
> > > >
> > > >         public void handleRow(Object valueObject) {
> > > >             final Map row = (Map) valueObject;
> > > >             map.put (row.get("SKU"), row.get("Description"));
> > > >         }
> > > >
> > > >         public Map getMap () {
> > > >             return map;
> > > >         }
> > > >
> > > >     }
> > > >
> > > > But I would like to move possibly that code out of my DAO code and into
> > > > iBatis SqlMap file.
> > > >
> > > > How could I do that
> > > >
> > > > TIA
> > > >
> > > > Pascal
> > > >
> > > >
> > 
> >


Mime
View raw message