Mapping values in nested object in myBatis?

Question

I want to map a nested object with one select query.

For example:

// parent class
public class Parent {
    private String name;
    private Child child;
}
    
// child class
public class Child {
    private name;
}

And I want to get whole parent class with one select query.

For example:

SELECT P.NAME, C.NAME from PARENT P, CHILD C

This is just example, please ignore specific grammar.

Is this possible?

It's possible, but you have to assign different column alias for C.NAME e.g. SELECT P.NAME, C.NAME C_NAME from .... For mapping, see the doc. It's explained as "nested results". — ave
– ave, Commented Apr 26, 2022 at 6:46

frxdude · Accepted Answer · 2022-04-26 04:34:32Z

1

In your Main

@MappedTypes(Parent.class)
@MapperScan("com.foo.mybatis.batis.mapper")
@SpringBootApplication
public class BatisApplication {...}

@MapperScan value should locate to your mapper package.

Use this in your interface. @Mapper @Select

import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;

import java.util.List;

@Mapper
public interface ParentMapper {

    @Select("select * from parents")
    List<Parent> findAll();
}

You can add your custom query in @Select("SELECT P.NAME, C.NAME from PARENT P, CHILD C")

answered Apr 26, 2022 at 4:34

frxdude

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2 Comments

sb0321 Over a year ago

Thank you for your kindness. But this is what i wanted. What i want is, single query for data, split and save them other objects. Anyway, Thanks.

frxdude Over a year ago

Checkout this @sb0321

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