这是一个创建于 1454 天前的主题，其中的信息可能已经有所发展或是发生改变。
项目地址： https://github.com/braisdom/ObjectiveSql
1 简单查询
@DomainModel
public class Blog {
private Long id;
private String title;
private Integer state;
@Relation(relationType = RelationType.BELONGS_TO)
private Author author;
}
根据单字段查询
| MyBatis | ObjectiveSQL |
public interface BlogMapper {
@Select("SELECT * FROM blog WHERE id = #{id}")
Blog selectBlog(int id);
}
...
BlogMapper mapper = session.getMapper(BlogMapper.class);
Blog blog = mapper.selectBlog(i);
|
Blog blog = Blog.queryByPrimaryKey(1); |
稍微复杂一点的查询
| MyBatis | ObjectiveSQL |
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="org.mybatis.example.BlogMapper">
<select id="findByTitle" resultType="Blog">
select * from Blog where title like '%#{title}%'
</select>
</mapper>
...
BlogMapper mapper = session.getMapper(BlogMapper.class);
Blog blog = mapper.findByTitle("标题");
|
public static Blog queryByTitle(String title) {
Query<Blog> query = createQuery();
query.where("title like ?", "%" + title + "%");
return query.queryFirst();
}
...
Blog blog = Blog.queryByTitle(1);
|
2 复杂查询
动态查询
| MyBatis | ObjectiveSQL |
<select id="findActiveBlogLike"
resultType="Blog">
SELECT * FROM BLOG
WHERE
<if test="state != null">
state > #{state}
</if>
<if test="title != null">
AND title like #{title}
</if>
<if test="author != null and author.name != null">
AND author_name like #{author.name}
</if>
</select>
...
BlogMapper mapper = session.getMapper(BlogMapper.class);
Blog blog = mapper.findActiveBlogLike(...);
|
Blog.Table blog = Blog.asTable();
Select select = new Select();
LogicalExpression eternalExpression = new EternalExpression();
if(state != null)
eternalExpression = eternalExpression.and(blog.state > state);
if(title != null)
eternalExpression = eternalExpression.and(blog.title.like(title));
if(author != null && author.name != null)
eternalExpression = eternalExpression.and(blog.author.like(author.name));
return select.from(blog).where(eternalExpression).execute();
|
关联查询
| MyBatis | ObjectiveSQL |
<mapper>
<resultMap type="Blog" id="blog">
<id column="id" property="id" />
...
<association property="author" javaType="Author">
...
</association>
</resultMap>
<select id="findBlog" parameterType="int" resultMap="blog">
...
</select>
</mapper>
...
BlogMapper mapper = session.getMapper(BlogMapper.class);
Blog blog = mapper. findBlog(...);
|
Blog blog = Blog.queryByPrimaryKey(1,
Blog.BELONGS_TO_AUTHOR)
|
 |
101
Braisdom OP join, sub query 这些都是传统 ORM 框架的弱势，有兴趣去这里，https://github.com/braisdom/ObjectiveSql
话题太长，这里讨论不方便 |
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102
liuhuan475 2020-12-14 14:32:38 +08:00  1
@Braisdom 为什么要用你这个框架 而不用 mybatis-plus
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103
Braisdom OP @liuhuan475 这个问题很好，是我后续要出更多文档进行比较的方向，至于为什么我目前先介绍几点：
1 ）动态代码生成：对于简单查询我只需要一个模型定义就可以，而 MyBatis 则需要一个多余的 Mapper 。 2 ）复杂表达式（算术，比较，逻辑）：我可能直接将 Java 的表达式转换成 SQL 表达式，例如：aTable.column + bTable.column...，而 MyBatis 只能通过字符串。 3 ）关联查询，分页查询：我只需要一个 Annotation，而 MyBatis 则需要 Mapper + XML 上面只是简单的描述，这些是我针对 MyBatis 的弱点进行的挑战。 |
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