JPA/Hibernate inserting into non existing table in spring boot application

Question

I am new to spring jpa/boot. I've created one-to-many relationship between Student and StudentCourse using JPA / Hibernate in a Spring boot application.

The database tables are student and student_course.

When I run the SchoolApplication.java, its failing with the error, 'table or view does not exist'.

It is a valid error as I have not created the table, student_course_list and only want to insert data in student and student_course tables.

Please can you advise why hibernate is looking for this additional table and how to resolve this issue?

Log

Hibernate: 
insert 
into
    student_course_list
    (student, course_list) 
values
    (?, ?)

Caused by: org.springframework.dao.InvalidDataAccessResourceUsageException: could not execute statement; SQL [n/a]; nested exception is org.hibernate.exception.SQLGrammarException: could not execute statement
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:242) ~[spring-orm-4.2.6.RELEASE.jar:4.2.6.RELEASE]

SchoolApplication.java

package com.school;

import java.util.ArrayList;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.transaction.annotation.Transactional;

import com.school.domain.Student;
import com.school.domain.StudentCourse;
import com.school.service.StudentServiceInterface;

@EntityScan(basePackages={"com.school.domain"})
@SpringBootApplication
public class SchoolApplication implements CommandLineRunner {

    @Autowired
    protected StudentServiceInterface studentService;

    public static void main(String[] args) {
        SpringApplication.run(SchoolApplication.class, args);
    }

    @Override
    @Transactional
    public void run(String... strings) throws Exception {

        StudentCourse sc1 = new StudentCourse();
        sc1.setCourseId(new Long(1));
        sc1.setEndDate(null);

        StudentCourse sc2 = new StudentCourse();
        sc2.setCourseId(new Long(2));
        sc2.setEndDate(null);

        //Course List
        List<StudentCourse> studentCourse = new ArrayList();

        studentCourse.add(sc1);
        studentCourse.add(sc2);

        Student student = new Student();
        student.setFirstName("test first");
        student.setLastName("test last");
        student.setCourseList(studentCourse);

        studentService.saveStudent(student);
}
}

Student

@Entity
@Table(name="student")
public class Student {

    @Id
    @Column(name="student_id")
    @GeneratedValue(strategy=GenerationType.AUTO, generator="student_seq_gen")
    @SequenceGenerator(name="student_seq_gen", sequenceName="SEQ_STUDENT")
    private Long studentId;

    @OneToMany( targetEntity=StudentCourse.class, cascade = {CascadeType.ALL} )
    private List<StudentCourse> courseList;

    @Column(name="first_name")
    private String firstName;

    @Column(name="last_name")
    private String lastName;

    @Column(name="gender")
    private char gender;

    @Column(name="date_of_birth")
    private Date dateOfBirth;

    @Column(name="email")
    private String email;

    @Column(name="city")
    private String city;

    // getter and setters
    .....
    .....

StudentCourse

@Entity
@Table(name="student_course")
public class StudentCourse {

    @Id
    @Column(name="student_course_id")
    @GeneratedValue(strategy=GenerationType.AUTO, generator="student_course_seq_gen")
    @SequenceGenerator(name="student_course_seq_gen", sequenceName="SEQ_STUDENT_COURSE")
    private Long studentCourseId;

    @Column(name="student_id")
    private Long studentId;

    @Column(name="course_id")
    private Long courseId;

    @Column(name="end_date")
    private Date endDate;

    // getter and setters
    .....
    .....

UPDATE:

StudentCourse.java:

@Entity
@Table(name="student_course")
public class StudentCourse {

    @Id
    @Column(name="student_course_id")
    @GeneratedValue(strategy=GenerationType.AUTO, generator="student_course_seq_gen")
    @SequenceGenerator(name="student_course_seq_gen", sequenceName="SEQ_STUDENT_COURSE")
    private Long studentCourseId;

    @JoinColumn(name="student_id", nullable = false, updatable = false, insertable = true)
    @ManyToOne
    private Student student;

    @Column(name="course_id")
    private Long courseId;

    @Column(name="end_date")
    private Date endDate;

Answer 1

You didn't define a JoinColumn (or JoinTable for ManyToMany) for your relationship. Hibernate is trying to create a table your student.courseList relationship property.

Change your Student class as follows:

// You shouldn't need targetEntity, as your collection has the TargetEntity.
// this parameter is only needed if the Generic type is not present 
// (e.g. private List courseList)
@OneToMany( cascade = {CascadeType.ALL}, mappedBy = "student" )
private List<StudentCourse> courseList;

Change your StudentCourse class as follows:

// Replace studentId with a Relationship
@JoinColumn(name="student_id")
@ManyToOne
private Student student;

This will tell Hibernate that the Relationship for Student -> StudentCourse is owned by Student and mapped by the student_id column in the student_course table.

Answer 2

You're not telling your application to scan for the entities. On your main class add the @EntityScan annotation. e.g.

@SpringBootApplication
@EntityScan(basePackages={"com.example.model", "com.example.student.model"})
public class SchoolApplication implements CommandLineRunner {
    ...
}

BTW, @ComponentScan is redundant, @SpringBootApplication is enough. If you're gonna look inside the SpringBootApplication class you'll see @ComponentScan there.