Mybatis queries using annotations

There are two main ways to use annotations MyBatis query:

First, the query twice, and then associate integration, without the use of contingency tables query.

1, Mapper file:

1      the @Select ( "the SELECT stu.id, stu.stu_key, stu.stu_no, stu.stu_name, stu.tel, stu.email_add, stu.birthdate, stu.gender, stu.school_id, stu.college_id, stu.major_id, stu.class_id, stu.description, stu.remark, stu.create_date, the WHERE stu.stu_key stu.update_date the FROM stu_info STU stuKey} = {# " )
 2      @Results ({
 . 3           
. 4              @Result (
 . 5                      // important: column: associated foreign key property: entity class attributes, not the field, StuInfo inside 
. 6                      column = "school_id", property = " schoolInfo " ,
 . 7                      One @One = (SELECT = "com.ahu.mapper.StuInfoMapper.getSchoolInfo" )
 . 8              )
 9     })
10     StuInfo showCompInfoByStuKey(String stuKey);
11 
12     @Select("SELECT school_info.id, school_info.school_id, school_info.school_name, school_info.create_time, school_info.update_time, school_info.remark FROM school_info WHERE school_info.school_id= #{school_info.school_id}")
13     SchoolInfo getSchoolInfo();

2, StuInfo entity class

. 1  @Data
 2  public  class StuInfo the implements the Serializable {
 . 3  
. 4      // @TableId (type = IdType.AUTO) // primary key database need to set the self-energizing self-energizing a primary key 
. 5      Private Integer ID;
 . 6      // stuKey used as the primary key, not update operations using the strategy 
. 7      @TableField (updateStrategy = FieldStrategy.NEVER)
 . 8      Private String stuKey;
 . 9      Private String stuno;
 10      Private String stuname;
 . 11      Private String password;
 12 is      Private String Tel;
 13 is     Private String emailAdd;
 14      / ** 
15       * @Description: annotation is converted back to the main @JsonFormat reception time format
 16       * Notes @DataFormAT mainly front-to-back time format conversion
 . 17       * / 
18 is      @JsonFormat (pattern = "the MM-dd-YYYY", TimeZone = "GMT +. 8" )
 . 19      @DateTimeFormat (pattern = "the MM-dd-YYYY" )
 20 is      Private a Date BIRTHDATE;
 21 is      Private String Gender;
 22 is      Private String schoolId;
 23 is      Private String collegeId;
 24-      Private String majorId;
 25      Private String classId;
 26     private String description;
27     private String remark;
28     @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
29     @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
30     private Date createDate;
31     @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
32     @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
33     private Date updateDate;
37 [)
to false     @TableField (= exist36the field does not exist in the database, using @TableField annotation process, with the use of table lookup//3534 is 
     
     private ClassInfo classInfo;
38     @TableField(exist = false)
39     private CollegeInfo collegeInfo;
40     @TableField(exist = false)
41     private MajorInfo majorInfo;
42     @TableField(exist = false)
43     private SchoolInfo schoolInfo;
44 }

Second, the query again, using the linked table query.

 1     @Select("SELECT stu.id, stu.stu_key, stu.stu_no, stu.stu_name,  stu.tel, stu.email_add, stu.birthdate, stu.gender, stu.school_id, sch.school_name, stu.college_id, col.college_name, stu.major_id, maj.major_name, stu.class_id, cla.class_name, stu.description, stu.remark, stu.create_date, stu.update_date FROM stu_info stu LEFT JOIN school_info sch ON stu.school_id = sch.school_id LEFT JOIN college_info col ON stu.college_id = col.college_id LEFT JOIN major_info maj ON stu.major_id = maj.major_id LEFT JOIN class_info cla ON stu.class_id = cla.class_id WHERE stu.stu_key = #{stuKey}")
 2     @Results({
 3             //@Result(column="school_id",property="schoolId"),
 4             @Result(
 5                     //Important: column: foreign key associated property: entity class attributes, not the field, StuInfo stuInfo inside 
. 6                      column = "school_id", property = "schoolInfo.schoolId" ) ,
 . 7              @Result (
 . 8                      // master mapping table is also done , or is empty null 
. 9                      column = "school_id", Property = "schoolId" ) ,
 10              @Result (column = "school_name", Property = "schoolInfo.schoolName" ),
 . 11              @Result (column = "college_id", Property = "collegeInfo.collegeId" ),
 12 is              @Result (column = "college_id", Property = "collegeId" ),
13             @Result(column = "college_name",property = "collegeInfo.collegeName"),
14             @Result(column = "major_id",property = "majorInfo.majorId"),
15             @Result(column = "major_id",property = "majorId"),
16             @Result(column = "major_name",property = "majorInfo.majorName"),
17             @Result(column = "class_id",property = "classInfo.classId"),
18             @Result(column = "class_id",property = "classId"),
19             @Result(column = "class_name",property = "classInfo.className"),
20     })
21     StuInfo showCompInfoByStuKey(String stuKey);

 

 

reference:

1、https://blog.csdn.net/qq_36228916/article/details/93881786

2、https://blog.csdn.net/z357904947/article/details/97975814