Доброго времени суток! Есть сущности
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@Data
@Entity
@Table(name = "student")
public class Student implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
private UUID studentId;
private String studentName;
private Integer studentStatus;
@ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
@JoinTable(name = "student_course",
joinColumns = @JoinColumn(name = "student_id", referencedColumnName = "studentId"),
inverseJoinColumns = @JoinColumn(name = "course_id", referencedColumnName = "courseId"))
private Set<Course> courses = new HashSet<>();
}
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@Data
@Entity
@Table(name = "course")
public class Course implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private UUID courseId;
private String courseCode;
private String courseName;
private BigDecimal courseCost;
@ManyToMany(cascade = CascadeType.ALL, mappedBy = "courses")
private Set<Student> students = new HashSet<>();
}
Есть таблицы
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CREATE TABLE IF NOT EXISTS student
(
id BIGSERIAL CONSTRAINT student_pk PRIMARY KEY,
student_id UUID,
student_name VARCHAR,
student_status INTEGER
);
CREATE TABLE IF NOT EXISTS course
(
id BIGSERIAL CONSTRAINT course_pk PRIMARY KEY,
course_id UUID,
course_code VARCHAR,
course_name VARCHAR,
course_cost NUMERIC
);
CREATE TABLE IF NOT EXISTS student_course
(
student_id UUID,
course_id UUID,
CONSTRAINT student_course_pk PRIMARY KEY (student_id, course_id)
);
Так исторически сложилось, что в таблицах student и course могут быть дубли по полям student_id и course_id
| id |
student_id |
student_name |
student_status |
| 1 |
854ff7f5-6802-4d56-b712-71ee4027fb89 |
student name |
1 |
| 2 |
854ff7f5-6802-4d56-b712-71ee4027fb89 |
student name |
1 |
| 3 |
854ff7f5-6802-4d56-b712-71ee4027fb89 |
student name |
1 |
| id |
course_id |
course_code |
course_name |
course_cost |
| 1 |
346d8e56-5f0e-4e11-b777-ec18df0c5c9f |
QWERT-1 |
QWERT-1 |
500 |
| 2 |
346d8e56-5f0e-4e11-b777-ec18df0c5c9f |
QWERT-1 |
QWERT-1 |
500 |
И при работе с сущностью student возникают ошибки
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Found shared references to a collection: Student.courses
Как можно в данном случае реализовать связь многие-ко-многим? Пробовал решение
https://stackoverflow.com/questions/77016233/hibernate-found-shared-references-to-a-collection-exception, но в итоге падает при попытке получения данных по student
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Exception occurred inside setter of Student.courses; nested exception is org.hibernate.PropertyAccessException with root cause
org.hibernate.LazyInitializationException: failed to lazily initialize a collection, no session or session was closed
