This is a personal note where I jot down the things I don't know and briefly summarize what I learn along the way. If you happen to know the answer to any of the unanswered questions, please leave a comment. Thank you.

Full Q&A List

[Answered]

1. What is the _long type?

• _long : maps to the long type
• long : maps to the Long type

Reference

• http://www.mybatis.org/mybatis-3/ko/configuration.html

2. How do you pass a list to handle IN (…)?

You can generate the (…) values for IN using the tag.

Reference

• http://pcdate.blogspot.com/2013/05/mybatis-foreach.html

3. The issue where mapping fails when using nested association columnPrefix?

When mapping an association with a nested columnPrefix, the prefix is appended cumulatively, so you have to write it in the form v_r_file_nm.

MyBatis Mapper file

<resultMap id="vodCollectionInfo" type="domain.entity.VodCollection" >
  <result column="vod_collection_seqno" property="vodCollectionNo"/>
  <result column="collection_title" property="collectionTitle"/>
  <association property="vodInfo" resultMap="vodInfo" columnPrefix="v_"/>
</resultMap>

<resultMap id="vodInfo" type="domain.entity.MediaVod" >
  <result column="vod_seqno" property="vodNo"/>
  <result column="vod_title" property="vodTitle"/>
  <association property="resourceInfo" resultMap="mediaResource" columnPrefix="r_"/>
</resultMap>

<resultMap id="mediaResourceMap" type="domain.entity.resource.MediaResource">
  <result column="resource_seqno" property="resourceSeqno"/>
  <result column="file_nm" property="fileName"/>
  <result column="file_size" property="fileSize" javaType="Integer"/>
</resultMap>

<select id="selectAllVodsByVodCollectionWithPaging" parameterType="domain.dto.VodCollectionPageMeta" resultMap="Common.vodCollectionInfo">
        SELECT vc.vod_collection_seqno,
               vc.collection_title,
               v.vod_seqno AS v_vod_seqno,
               v.vod_title AS v_vod_title,
               rv.original_file_nm AS v_r_original_file_nm,
               rv.file_nm AS v_r_file_nm,
               rv.width AS v_r_width,
               rv.height AS v_r_height
        FROM media_vod_collection AS vc
                 INNER JOIN media_vod_collection_mapping AS vcm
                            ON vcm.vod_collection_seqno = vc.vod_collection_seqno
                 INNER JOIN media_vod AS v
                            ON v.vod_seqno = vcm.vod_seqno
                 LEFT JOIN media_resource AS rv
                           ON rv.resource_seqno = v.resource_seqno
        WHERE vc.vod_collection_seqno = #{vodCollectionNo}
    </select>

Reference

• https://androphil.tistory.com/733?category=423961

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[Unanswered Questions]

- Can you write unit tests in MyBatis using the @Transactional annotation?

• It doesn't work well

Reference

• http://barunmo.blogspot.com/2013/06/mybatis.html
• https://otamot.com/64
• https://wedul.site/133
• https://examples.javacodegeeks.com/enterprise-java/spring/write-transactional-unit-tests-spring/
• https://mycup.tistory.com/185

- What is the association attribute in MyBatis?

• It's used when a resultMap contains another object, and association handles a "has one" type relationship.
• For a collection, it's used when handling a "has many" type relationship.

Reference

• http://noveloper.github.io/blog/spring/2015/05/31/mybatis-assocation-collection.html

- Does MyBatis support aliases for namespaces?

• No

Reference

• https://github.com/mybatis/mybatis-3/issues/1160

- I often see cdata in MyBatis. Why is it used?

Reference

• https://epthffh.tistory.com/entry/Mybatis-%EC%97%90%EC%84%9C-CDATA-%EC%82%AC%EC%9A%A9%ED%95%98%EA%B8%B0