ibatis多表查詢

 

我們先來看看這兩張表

表名：tbl_Student

字段：ID,NAME,CLASS_ID

表名：tbl_Class

字段：ID，NAME

很簡單的一個邏輯，班級下邊有很多學生。我們先對學生表做簡單的查詢。

public class Student

{

    private String id;

    private String name;

    private Stirng birth;

    private String class_id;

    .......................

}

<typeAlias alias="StudentClass" type="model.Student"></typeAlias>

<sql >

    <![CDATA[

        select ID,NAME,CLASS_ID

        from tbl_Student

    ]]>

</sql>

<resultMap >

    <result property="id" column="ID" />

    <result property="name" column="NAME" />

    <result property="class_id" column="CLASS_ID" />

</resultMap>

<select parameterClass="java.util.Map" resultMap="StudentMap">

    <include ref />

</select>

public class StudentDto

{

     private String id;

     private String name;

     private Stirng birth;

     private String class_id;

     private String class_name;

     ......................

}

在原有的StudentMapper.xml文件中加入一下內容：

<typeAlias alias="StudentDtoClass" type="dto.StudentDto"></typeAlias>

<resultMap >

    <result property="id" column="ID" />

    <result property="name" column="NAME" />

    <result property="class_id" column="CLASS_ID" />

    <result property="class_name" column="CLASS_NAME" />

</resultMap>

<sql >

    <![CDATA[

        select s.ID as id,s.NAME as name,s.CLASS_ID as class_id,c.name as class_name

        from tbl_Student s,tbl_Class c 

        where s.class_id = c.id

    ]]>

</sql>

<select parameterClass="java.util.Map" resultMap="StudentDtoMap">

    <include ref />

</select>