MyBatis 3.2.8 Select Select columns from a row as a List<Object>

[sandeep reddy]

Hi All,

I have a scenario, where I SELECT all  cars from CARS_TABLE and build a Car object. The challenge I'm facing is to build a List<Feature> from a single row. I tried several ways to this, but couldn't get what I needed.

Below is the table and corresponding java class and XML Mapping. I appreciate if someone can help me resolve this.

CAR_TABLE

ID

MANUFACTURER

YEAR

MODEL

FEATURE_X

FEATURE_Y

Car.java

private int id;

private String manufacturer;

private String year;

private String model;

private Features features;

Features.java

private List<Feature> feature;

Feature.java

private featureType;

Mapping

<resultMap id="BaseResultMap" type="com.eval.Car" >

    <id column="ID" property="ID" jdbcType="NUMERIC" />

    <result column="MANUFACTURER" property="manufacturer" jdbcType="VARCHAR" />

    <result column="YEAR" property="year" jdbcType="VARCHAR" />

    <result column="MODEL" property="model" jdbcType="VARCHAR" />

  <collection property="features" resultMap="FeaturesMap">

    </collection>

  </resultMap>

  

  

  <resultMap id="FeaturesMap" type="com.eval.Features" >

     <collection property="phoneRecord" ofType="com.eval.Feature">

    <result property="featureType" column="feature1"/>                    

    <result property="featureType" column="feature2"/>

    </collection>

  </resultMap>

  

 // I believe the above mapping is not the right way as both columns map to the same property and hence result in a single object. All I need is a List of features i.e List<Feature> where feature1 will be one Feature and feature2 will be another Feature.

SELECT QUERY

  <select id="selectCars" resultMap="BaseResultMap" >

    select *

    from CARS_TABLE

  </select>

[Guy Rouillier]

select ID, MANUFACTURER, YEAR, MODEL, FEATURE_X from CARS_TABLE
union
select ID, MANUFACTURER, YEAR, MODEL, FEATURE_Y from CARS_TABLE

On 11/11/2014 6:31 PM, sandeep reddy wrote:
>
> Hi All,
> I have a scenario, where I SELECT all cars from CARS_TABLE and build a
> Car object. The challenge I'm facing is to build a List<Feature> from a
> single row. I tried several ways to this, but couldn't get what I needed.
>
> Below is the table and corresponding java class and XML Mapping. I
> appreciate if someone can help me resolve this.
>

> *CAR_TABLE*

> ID
> MANUFACTURER
> YEAR
> MODEL
> FEATURE_X
> FEATURE_Y
>
>

> *Car.java*

> private int id;
> private String manufacturer;
> private String year;
> private String model;
> private Features features;
>
>

> *Features.java*
> private List<Feature> feature;
>
>
> *Feature.java*
> private featureType;
>
>
>
> *Mapping*

>
>
> <resultMap id="BaseResultMap" type="com.eval.Car" >
>
> <id column="ID" property="ID" jdbcType="NUMERIC" />
> <result column="MANUFACTURER" property="manufacturer"
> jdbcType="VARCHAR" />
> <result column="YEAR" property="year" jdbcType="VARCHAR" />
> <result column="MODEL" property="model" jdbcType="VARCHAR" />
> <collection property="features" resultMap="FeaturesMap">
> </collection>
> </resultMap>
> <resultMap id="FeaturesMap" type="com.eval.Features" >
> <collection property="phoneRecord" ofType="com.eval.Feature">

> <*result property="featureType" column="feature1"/> *
> * <result property="featureType" column="feature2"/>*

> </collection>
> </resultMap>
> // I believe the above mapping is not the right way as both columns
> map to the same property and hence result in a single object. All I need
> is a List of features i.e List<Feature> where feature1 will be one
> Feature and feature2 will be another Feature.
>
>

> *SELECT QUERY*

> <select id="selectCars" resultMap="BaseResultMap" >
> select *
> from CARS_TABLE
> </select>
>

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[sandeep reddy]

Hello,

That's right but the problem is I shouldn't use anything else other than SELECT * from CARS_TABLE. More specifically, there will be a VIEW created over CARS_TABLE that cannot be changed. The VIEW will be something like SELECT ID, MANUFACTURER, YEAR, MODEL, FEATURE_X from CARS_TABLE with some conditions.

> <mailto:mybatis-user+unsub...@googlegroups.com>.

[Guy Rouillier]

What happens to FEATURE_Y in that view? You can union multiple queries
of views just as you can of base tables.

On 11/11/2014 7:37 PM, sandeep reddy wrote:
>
> Hello,
> That's right but the problem is I shouldn't use anything else other than

> *SELECT * from CARS_TABLE*. More specifically, there will be a VIEW

> > an email to mybatis-user...@googlegroups.com <javascript:>
> > <mailto:mybatis-user...@googlegroups.com <javascript:>>.

> > For more options, visit https://groups.google.com/d/optout

> <https://groups.google.com/d/optout>.

>
>
> --
> Guy Rouillier
>
> ---
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> http://www.avast.com
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[sandeep reddy]

My bad, its select ID, MANUFACTURER, YEAR, MODEL, FEATURE_X, FEATURE_Y from CARS_TABLE. My question is more of building the List<Feature> from a single row/

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>
>
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>
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[Condor]

I would use the feature1 etc. approach.

Your class can still contain a list of features, but you would write an additional setter for every feature separately.