MyBatis的基本注解

 MyBatis的基本注解：

增删改查

@Select("select * from teacher")

 public List<Teacher> selAll();

 

 //增删改返回值都是int

 @Insert("insert into teacher values(default,#{name})")

 public int add(Teacher teacher);

 

 @Update("update teacher set name=#{name} where id=#{id}")

 public int update(Teacher teacher);

 

 @Delete("delete from teacher where id=#{id}")

 public int delete(int id);

　　

MyBatis映射

１.普通映射

 

@Select("select * from mybatis_Student where id=#{id}")  
public Student getStudent(int id);  
@Insert("insert into mybatis_Student (name, age, remark, pic,grade_id,address_id) values (#{name},#{age},#{remark}, #{pic},#{grade.id},#{address.id})")  
public int insert(Student student);  
@Update("update mybatis_Student set name=#{name},age=#{age} where id=#{id}")  
public int update(Student student);  
@Delete("delete from mybatis_Student where id=#{id}")  
public int delete(int id); 

 

　2.结果集映射

@Select("select * from mybatis_Student")  
@Results({  
    @Result(id=true,property="id",column="id"),  
    @Result(property="name",column="name"),  
    @Result(property="age",column="age")  
})  
public List<Student> getAllStudents(); 

３.关系映射

一对一

@Select("select * from mybatis_Student")  
@Results({  
    @Result(id=true,property="id",column="id"),  
    @Result(property="name",column="name"),  
    @Result(property="age",column="age"),  
    @Result(property="address",column="address_id",one=@One(select="com.skymr.mybatis.mappers.AddressMapper.getAddress"))  
})  
public List<Student> getAllStudents();

　一对多

@Select("select * from mybatis_grade where id=#{id}")  
    @Results({  
        @Result(id=true,column="id",property="id"),  
        @Result(column="grade_name",property="gradeName"),  
        @Result(property="students",column="id",many=@Many(select="com.skymr.mybatis.mappers.Student2Mapper.getStudentsByGradeId"))  
    })  
    public Grade getGrade(int id);