How to use Spring Data JPA Repository to query from 2 tables?

Question

I have 2 tables say Student and Teacher and say Student has a Many-To-One relationship to Teacher and say, teacherId serves as the foreign key.

How can I use spring data JPA repo methods, in a way - findByTeacherName, if I want to query something like below,

select * from Student S, Teacher T      where T.teacherName = 'SACHIN' and S.teacherId = T.teacherId 

Note : Here I wanna query using only StudentRepository, which is created using StudentHibernateMapping class that has a relationship to TeacherHibernateMapping class

Any help will greatly be appreciated.

Answer 1

There will be a repository method on StudentRepository

List<Student> findByTeacher_TeacherId(String teacherId); 

your entityClass should be like..

@Entity Class Student {   @Id   String studentId;   @ManyToOne   private Teacher teacher; } 

and Teacher Class would be..

@Entity Class Teacher {   @Id   private String teacherId; } 

Here the key thing you need to know is:

findBy + (the foreign key member of student class with first letter Upper) + underscore +the data member of Teacher Class with first letter UpperCase +(String teacherId);

this will give you a list of students belonging to that teacher