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From "Ted Schrader" <teds.mailing.li...@gmail.com>
Subject Re: Semi complex mapping question
Date Wed, 21 Mar 2007 15:55:12 GMT
Hi Mike,

Okay, I think I know what the immediate problem is.  Again, your
nested query goes like this:
    <select id="getCurvePoints" resultMap="CurvePointBOResult">
        select
            VALUE, OFFSET
        from dbo.CURVE
        where CURVE_NAME = #curveName#
          and CURVE_CATEGORY = #curveCategory#
    </select>

So, if you pass in null as your parameter object:
       >> getSqlMapClientTemplate().queryForList("selectAll", null);

iBATIS will have big problems inserting the #curveName# and
#curveCategory# values.  Since the <select> is nested under the name
"curvePoints, that's why you see

--- Check the result mapping for the >>>>>'curvePoints'<<<<<<
property.
--- Cause: java.lang.NullPointerException ;

(>>>> and <<<<< added for emphasis).


In regards to getting suggestions for better approaches, seeing some
example data would help.  Does your data look something like this?

CURVE_NAME   CURVE_CATEGORY  OFFSET   VALUE
----------------------------------------------------------------------------------------
'45DegreeCurve'    'boring'                      0               0
'45DegreeCurve'    'boring'                      1               1
'coolCurve'            'exponential'              0               0
'coolCurve'            'exponential'              1               1
'coolCurve'            'exponential'              2               4
'coolCurve'            'exponential'              3               9
'coolCurve'            'exponential'              4               16
'coolCurve'            'exponential'              5               25


One strategy is to use the "groupBy" attribute of a result map.
However, I'm not sure if this will easily work with your composite key
set-up.  Again, this is why seeing some example data would be helpful.

Also, I admit that I have not used N+1 solutions, but I'm sure others
on the list will lend a hand once we can give them more details.

Ted


On 21/03/07, Mikael Andersson <mail.micke@gmail.com> wrote:
> Hi Ted,
> just started using iBATIS and the manual contains a similar approach, that
> is why I did it that way. I figured I would get that working and then tackle
> the problem of N+1 select statements.
>
> The table contains lots and lots of curves, where each curve has many curve
> points. Stupid design I know, loads of redundancy...
> The primary keys in the table are CURVE_NAME,CURVE_CATEGORY and OFFSET ,
> which gives me one point on a curve.
>
> The columns CURVE_NAME and CURVE_CATEGORY whil give me a list of points
> defining a complete curve.
>
> Hope the above makes some sence.
>
> I used Abator to generate the code, and then manually changed stuff. This is
> how it is called in the DAO:
>
> public List<CurveBO> selectAll() {
>         List<CurveBO> list =
> (List<CurveBO>)getSqlMapClientTemplate().queryForList("selectAll",
> null);
>         return list;
> }
>
>
> Thanks,
>  Mike
>
>
> On 21/03/07, Ted Schrader <teds.mailing.lists@gmail.com > wrote:
> > Hi Mike,
> >
> > How are you calling the mapped statement on the Java side?
> >
> > Also, it's not clear why you're going to the trouble of a nested
> > select ("getCurvePoints") when it seems from your table design that
> > there will be one and only one x-y pair for a primary key.  Would you
> > elaborate on why you are attempting this approach?
> >
> > Ted
> >
> > On 21/03/07, Mikael Andersson <mail.micke@gmail.com> wrote:
> > > Hi,
> > > I'm new to iBATIS and need some help with a problem I'm having.
> > >
> > > I have a table called CURVE which contains curve points for loads of
> curves
> > > (graph curves), where each curve can have a dynamic number of curve
> points.
> > >
> > > Table structure:
> > > CURVE_NAME | CURVE_CATEGORY | OFFSET | VALUE
> > >
> > > CURVE_NAME and CURVE_CATEGORY are the primary keys, OFFSET is the
> x-value
> > > and VALUE is the y-value
> > >
> > > SqlMap :
> > >
> > > <resultMap id="CurveBOResult" class=" test.bo.CurveBO">
> > >     <result column="CURVE_NAME" jdbcType="CHAR" property="curveName"/>
> > >    <result column="CURVE_CATEGORY" jdbcType="CHAR"
> > > property="curveCategory"/>
> > >     <result property="curvePoints" select="getCurvePoints"
> > >
> column="{curveName=CURVE_NAME,curveCategory=CURVE_CATEGORY}"/>
> > >   </resultMap>
> > >
> > >   <resultMap id="CurvePointBOResult" class=" test.bo.CurvePointBO">
> > >     <result column="VALUE" jdbcType="DOUBLE" property="value"/>
> > >     <result column="OFFSET" jdbcType="DOUBLE" property="offset"/>
> > >   </resultMap>
> > >
> > >     <select id="selectAll" resultMap="CurveBOResult">
> > >         select distinct
> > >            CURVE_NAME, CURVE_CATEGORY
> > >         from dbo.CURVE
> > >     </select>
> > >
> > >     <select id="getCurvePoints" resultMap="CurvePointBOResult">
> > >         select
> > >             VALUE, OFFSET
> > >         from dbo.CURVE
> > >         where CURVE_NAME = #curveName#
> > >           and CURVE_CATEGORY = #curveCategory#
> > >     </select>
> > >
> > > CurveBO.java has a:  private List<CurvePointBO> curvePoints = new
> > > ArrayList<CurvePointBO>(19);
> > > with public getter and setter.
> > >
> > > When I run this I get the following error message:
> > >
> > > org.springframework.jdbc.UncategorizedSQLException:
> > > SqlMapClient operation; uncategorized SQLException for SQL []; SQL state
> > > [null]; error code [0];
> > > --- The error occurred in sqlmap/dbo_CURVES_SqlMap.xml.
> > >  --- The error occurred while applying a result map.
> > > --- Check the dbo_CURVE.CreditSpreadBOResult.
> > > --- Check the result mapping for the 'curvePoints' property.
> > > --- Cause: java.lang.NullPointerException ; nested exception is
> > > com.ibatis.common.jdbc.exception.NestedSQLException:
> > > --- The error occurred in sqlmap/dbo_CURVE_SqlMap.xml.
> > > --- The error occurred while applying a result map.
> > > --- Check the dbo_CURVE.CurveBOResult.
> > > --- Check the result mapping for the 'curvePoints' property.
> > > --- Cause: java.lang.NullPointerException
> > > com.ibatis.common.jdbc.exception.NestedSQLException:
> > > --- The error occurred in sqlmap/dbo_CURVE_SqlMap.xml.
> > > --- The error occurred while applying a result map.
> > > --- Check the dbo_CURVE.CurveBOResult.
> > > --- Check the result mapping for the 'curvePoints' property.
> > > --- Cause: java.lang.NullPointerException
> > >      at
> > >
> com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeQueryWithCallback(GeneralStatement.java:188)
> > >     at
> > >
> com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeQueryForList
> (GeneralStatement.java
> > > :123)
> > >     at
> > >
> com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForList(SqlMapExecutorDelegate.java:615)
> > >     at
> > >
> com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForList
> (SqlMapExecutorDelegate.java:589)
> > >     at
> > >
> com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.queryForList(SqlMapSessionImpl.java:118)
> > >     at
> > >
> org.springframework.orm.ibatis.SqlMapClientTemplate$3.doInSqlMapClient
> (SqlMapClientTemplate.java:231)
> > >     at
> > >
> org.springframework.orm.ibatis.SqlMapClientTemplate.execute(SqlMapClientTemplate.java:168)
> > >     at
> > >
> org.springframework.orm.ibatis.SqlMapClientTemplate.executeWithListResult
> (SqlMapClientTemplate.java:190)
> > >     at
> > >
> org.springframework.orm.ibatis.SqlMapClientTemplate.queryForList
> > > (SqlMapClientTemplate.java:229)
> > >     at
> > >
> test.dao.CurveBODAOImpl.selectAll(CreditSpreadBODAOImpl.java
> :40)
> > >     at
> > >
> testa.dao.TestCurveBODAOImpl.testSelectdAll(TestCreditSpreadBODAOImpl.java:38)
> > >     at sun.reflect.NativeMethodAccessorImpl.invoke0
> (Native
> > > Method)
> > >     at
> > > sun.reflect.NativeMethodAccessorImpl.invoke
> (NativeMethodAccessorImpl.java:39)
> > >     at
> > >
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> > >     at java.lang.reflect.Method.invoke (Method.java:585)
> > >     at
> junit.framework.TestCase.runTest(TestCase.java:154)
> > >     at
> junit.framework.TestCase.runBare(TestCase.java:127)
> > >     at
> > >
> junit.framework.TestResult$1.protect(TestResult.java:106)
> > >     at junit.framework.TestResult.runProtected
> > > (TestResult.java:124)
> > >     at junit.framework.TestResult.run(TestResult.java:109)
> > >     at junit.framework.TestCase.run(TestCase.java:118)
> > >     at
> > > junit.framework.TestSuite.runTest(TestSuite.java :208)
> > >     at junit.framework.TestSuite.run (TestSuite.java:203)
> > >     at
> > >
> org.eclipse.jdt.internal.junit.runner.junit3.JUnit3TestReference.run(JUnit3TestReference.java:128)
> > >     at
> > > org.eclipse.jdt.internal.junit.runner.TestExecution.run
> (TestExecution.java:38)
> > >      at
> > >
> org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:460)
> > >     at
> > >
> org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests
> (RemoteTestRunner.java:673)
> > >     at
> > >
> org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run
> > > (RemoteTestRunner.java:386)
> > >     at
> > >
> org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main
> (RemoteTestRunner.java:196)
> > > Caused by: java.lang.NullPointerException
> > >     at
> > >
> com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.endTransaction
> > > (SqlMapExecutorDelegate.java:782)
> > >     at
> > >
> com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.endTransaction(SqlMapSessionImpl.java:176)
> > >     at
> > >
> com.ibatis.sqlmap.engine.impl.SqlMapClientImpl.endTransaction(SqlMapClientImpl.java
> > > :154)
> > >     at
> > >
> com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.autoEndTransaction(SqlMapExecutorDelegate.java:883)
> > >     at
> > >
> com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForList(SqlMapExecutorDelegate.java
> > > :622)
> > >     at
> > >
> com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForList(SqlMapExecutorDelegate.java:589)
> > >     at
> > >
> com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.queryForList(
> SqlMapSessionImpl.java:118)
> > >     at
> > >
> com.ibatis.sqlmap.engine.impl.SqlMapClientImpl.queryForList(SqlMapClientImpl.java:95)
> > >     at
> > >
> com.ibatis.sqlmap.engine.mapping.result.loader.ResultLoader.getResult
> (ResultLoader.java:72)
> > >     at
> > >
> com.ibatis.sqlmap.engine.mapping.result.loader.ResultLoader.loadResult
> > > (ResultLoader.java:59)
> > >     at
> > >
> com.ibatis.sqlmap.engine.mapping.result.BasicResultMap.getNestedSelectMappingValue
> (BasicResultMap.java:502)
> > >     at
> > >
> com.ibatis.sqlmap.engine.mapping.result.BasicResultMap.getResults(BasicResultMap.java
> > > :340)
> > >     at
> > >
> com.ibatis.sqlmap.engine.execution.SqlExecutor.handleResults
> (SqlExecutor.java:381)
> > >     at
> > >
> com.ibatis.sqlmap.engine.execution.SqlExecutor.handleMultipleResults(SqlExecutor.java:301)
> > >     at
> > >
> com.ibatis.sqlmap.engine.execution.SqlExecutor.executeQuery
> > > (SqlExecutor.java:190)
> > >     at
> > >
> com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.sqlExecuteQuery(GeneralStatement.java:205)
> > >     at
> > >
> com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeQueryWithCallback
> > > (GeneralStatement.java:173)
> > >     ... 28 more
> > >
> > >
> > > Have a feeling that I missed something simple :)
> > >
> > > Cheers,
> > >  Mike
> > >
> > >
> >
>
>

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