Mybatis 一对多和多对一关联查询问题一对多和多对一关联查询问题
主要介绍了Mybatis 一对多和多对一关联查询问题,需要的朋友可以参考下
首先 数据库量表之间字段关系(没有主外键)
studentmajor表的id字段对应student表里major字段
两个实体类两个实体类
package com.model;
import java.util.Date;
public class Student {
private Integer sno;
private String sname;
private String ssex;
private Integer sclass;
private StudentMajor studentmajor;
public Student() {
super();
}
public Student(Integer sno, String sname, String ssex, Integer sclass, StudentMajor studentmajor) {
super();
this.sno = sno;
this.sname = sname;
this.ssex = ssex;
this.sclass = sclass;
this.studentmajor = studentmajor;
}
public StudentMajor getStudentmajor() {
return studentmajor;
}
public void setStudentmajor(StudentMajor studentmajor) {
this.studentmajor = studentmajor;
}
public Integer getSno() {
return sno;
}
public void setSno(Integer sno) {
this.sno = sno;
}
public String getSname() {
return sname;
}
public void setSname(String sname) {
this.sname = sname;
}
public String getSsex() {
return ssex;
}
public void setSsex(String ssex) {
this.ssex = ssex;
}
@Override
public String toString() {
return "Student [sno=" + sno + ", sname=" + sname + ", ssex=" + ssex + ", sclass=" + sclass + ", studentmajor="
+ studentmajor + "]";
}
public Integer getSclass() {
return sclass;
}
public void setSclass(Integer sclass) {
this.sclass = sclass;
}
}
package com.model;
import java.util.List;