I've three associated records (Conference, SubmissionRecord, SubmissionAuthorRecord). Every SubmissionRecord has a Conference object and has a List<SubmissionAuthorRecord>.
When I delete a Conference record if the SubmissionRecord is associated with that Conference, it should cascade and delete as well. However, I keep getting a java.sql.SQLIntegrityConstraintViolationException: Cannot delete or update a parent row: a foreign key constraint fails (`viz`.`submission_record_author_set`, CONSTRAINT `FKgnqq52l26bitkmojk1oiuaki1`
FOREIGN KEY (`submission_record_s_id`) REFERENCES `submission_record` (`s_id`)) error message.
The table submission_record_author_set is create automatically and I have no entity that maps to it.
I understand the issue lies in the fact that the submission_record_author_set rows are preventing the SubmissionRecord from being deleted and have tried the #PreRemove method described here (How to remove entity with ManyToMany relationship in JPA (and corresponding join table rows)?) but to no avail. Maybe there's an issue with the ManyToMany annotation? Cause I do not see the equivalent annotation in the SubmissionAuthorRecord either.
#Entity
public class SubmissionRecord {
#Id
#GenericGenerator(name = "UseExistingIdOtherwiseGenerateUsingIdentity", strategy = "xyz")
#GeneratedValue(generator = "UseExistingIdOtherwiseGenerateUsingIdentity")
#JsonSerialize(using = ToStringSerializer.class)
#Column(name = "s_id")
private Long id;
#Exportable(name = "Submission Id", nameInDB = "s_submission_id")
#Column(name = "s_submission_id")
private String submissionId;
// internal set of authors of the associated
#ManyToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
#JsonIgnore
private List<SubmissionAuthorRecord> authorSet;
#JoinColumn(name="conference_id")
#ManyToOne(fetch = FetchType.EAGER)
#OnDelete(action = OnDeleteAction.CASCADE)
private Conference conference;
//...
}
#Entity
public class Conference {
#Id
#GenericGenerator(name = "UseExistingIdOtherwiseGenerateUsingIdentity", strategy = "xyz")
#GeneratedValue(generator = "UseExistingIdOtherwiseGenerateUsingIdentity")
#JsonSerialize(using = ToStringSerializer.class)
private Long id;
private String creatorIdentifier;
private String conferenceName;
private String conferenceYear;
}
#Entity
public class SubmissionAuthorRecord {
#Id
#GenericGenerator(name = "UseExistingIdOtherwiseGenerateUsingIdentity", strategy = "xyz")
#GeneratedValue(generator = "UseExistingIdOtherwiseGenerateUsingIdentity")
#JsonSerialize(using = ToStringSerializer.class)
#Column(name = "s_author_id")
private Long id;
private String dataSet;
#Column(name = "s_author_name")
private String name;
}
The submission_author_record_set table looks like the following:
Related
I have to entities modeled Session and Speaker, with ManyToMany relationship, and I wanted to delete an instance of Session, but in the DB it is the foreign key of another table. Below is the entity model
#Entity(name = "sessions")
public class Session {
// attributes do not respect camel case notations because they
// need to match table notations in order to auto bind without annotations
// otherwise that is done with #Column annotation
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long session_id;
private String session_name;
private String session_description;
private String session_length;
#OnDelete(action = OnDeleteAction.CASCADE)
#ManyToMany()
#JoinTable(
name = "session_speakers",
joinColumns = #JoinColumn(name = "session_id"),
inverseJoinColumns = #JoinColumn(name = "speaker_id")
)
private List<Speaker> speakers;
public Session() {
}
I tried to use OnDelete Cascade, but it still didn't work. (I did read that it is not advised to use on ManyToMany relationship)
#RequestMapping(value = "{id}", method = RequestMethod.DELETE)
public void delete(#PathVariable Long id){
sessionRepo.deleteById(id);
}
EDIT:
here is also the Speaker entity
#Entity(name = "speakers")
public class Speaker {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long speaker_id;
private String first_name;
private String last_name;
private String title;
private String company;
private String speaker_bio;
#Lob
#Type(type = "org.hibernate.type.BinaryType")
private Byte[] speaker_photo;
public Byte[] getSpeaker_photo() {
return speaker_photo;
}
public void setSpeaker_photo(Byte[] speaker_photo) {
this.speaker_photo = speaker_photo;
}
#ManyToMany(mappedBy = "speakers")
#JsonIgnore// added to resolve serialization issues
private List<Session> sessions;
When I make changes to one attribute of an entity, it also somehow gets changed for every other entity that uses that entity. I have three entities as you can see below.
Students and courses need to have a many-to-many relationship between them and the course needs to have a one-to-many relationship with course lectures.
When I make changes to courses or course lectures that belong to a specific student by doing #Transactional student.getCourse().get(0).setTitle("whatever"), those changes are also reflected in other students who share the same course. I need help with this, thank you
The student class
public class Student {
#Id
#SequenceGenerator(
name = "student_sequence",
sequenceName = "student_sequence",
allocationSize=1
)
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "student_sequence")
private Long studentId;
private String fullName;
#Column(name = "email_address", nullable = false)
private String email;
private String username;
private String password;
#ManyToMany(mappedBy = "students", fetch = FetchType.EAGER)
private List<Course> courses ;
public void addCourse(Course course) {
if (courses == null) {
courses = new ArrayList<>();
}
courses.add(course);
}
Course Class
public class Course {
#Id
#SequenceGenerator(
name = "course_sequence",
sequenceName = "course_sequence",
allocationSize = 1
)
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "course_sequence")
private Long courseId;
private String title;
private double courseRating = 0;
private LocalDateTime createdAt = LocalDateTime.now();
private double completedProgress = 0;
#Embedded
private CourseInformation courseInformation;
#OneToMany(cascade = CascadeType.MERGE, fetch = FetchType.EAGER)
#JoinColumn(name = "course_id", referencedColumnName = "courseId")
private List<CourseLecture> courseLectures;
#ManyToMany(
cascade = CascadeType.MERGE,
fetch = FetchType.LAZY
)
#JoinTable(
name = "student_course_mapping",
joinColumns = #JoinColumn(
name = "course_id",
referencedColumnName = "courseId"
),
inverseJoinColumns = #JoinColumn(
name = "student_id",
referencedColumnName = "studentId"
)
)
#ToString.Exclude
private List<Student> students;
There is no relationship mapping in the CourseLecture class.
This is not wrong, but just the way JPA works.
Technically it works, because they all reference the same instance as JPA guarantees to always return the same instance for a given class and id in single session.
If you don't want that you'd have to do the work either in different sessions, or you have to change your data model, so that each student has their own course. Of course this would be a strange model.
Update based on your comment:
Looks like indeed you need a different model, instead of Student -N-M-> Course you need something like Student -1-N-> Attendance -N-1-> Course, making the mapping table of your relationship into an entity and allowing it to store extra data that is specific to Student AND Course
I have 2 class
public class User {
#Id
#Column(name = "id")
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
private String age;
#OneToOne
#JoinColumn(name = "address_id", referencedColumnName = "id")
private Address address;
}
and
public class Address {
#Id
#Column(name = "id")
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String building;
private String country;
#OneToOne(mappedBy = "address")
private User user;
}
in my table address, I have a few rows.
When I insert table user with data
{
"id":null,
"name":"Foo",
"age":"18",
"address":{
"id":1,
"building":"Too",
"country":"ABS"
}
}
Table user have 1 row with address_id =1.
I insert same data as above
Table user have 2 row with address_id =1.
My answer is: why 2 table connected by one to one can happen the above case?
You can find your answer here
Why #OneToOne is allowing duplicate associations?
Basically, #JoinColumn(name = "address_id", referencedColumnName = "id") alone doesn't serve the semantics of one-to-one in the database, you need to add unique=true into the #JoinColumn, which makes it #JoinColumn(name = "address_id", referencedColumnName = "id", unique = true).
Side-note: I suggest you drop your tables and then re-creating them before trying this out. If you are using Hibernate, you can set hibernate.hbm2ddl.auto to create-drop
Hi I have couple of Entity classes as below, using lombok for getter and setters
Parent Entity Class have
#Table(name = "PARTY")
#Entity
public class Party {
#Id
#Column(name = "PARTY_ID")
private Long partyId;
#OneToMany(targetEntity = DVLoanParticipants.class,cascade = CascadeType.ALL)
#JoinColumn(name = "PARTY_ID")
#MapKey(name="dvpParticipantName")
#LazyCollection(LazyCollectionOption.FALSE)
private Map<String, DVLoanParticipants> dvLoanParticipantsMap;
}
Child Entity Class have
#Table(name = "DV_LOAN_PARTICIPANTS")
#Entity
public class DVLoanParticipants implements Serializable {
#Id
#Column(name = "PARTY_ID")
private Long partyId;
#Id
#Column(name = "DVP_PARTICIPANT_NAME")
private String dvpParticipantName;
#Column(name = "DVP_PARTICIPANT_TYPE")
private String dvpParticipantType;
}
In service class i am calling save operation as
repository.save(parentEntityObject);
I am able to execute update statements ,but when i try to insert new row for child entity class i am getting an error saying
cannot insert NULL into ("ABC"."DV_LOAN_PARTICIPANTS"."PARTY_ID")
But if i print the parentEntityObject just before the save operation i see the values like
(partyId=12345678, dvpParticipantName=XYZ, dvpParticipantType=VKP)
I see the query formed as
insert
into
DV_LOAN_PARTICIPANTS
(DVP_PARTICIPANT_TYPE, PARTY_ID, DVP_PARTICIPANT_NAME)
values
(?, ?, ?)
Just before te save i am seeing valules in the Object
Builder=DVLoanParticipants(partyId=123456, dvpParticipantName=Builder,
dvpParticipantType=Individual)
Update
This is the setting part for values
DVLoanParticipants dvLoanParticipants = new
DVLoanParticipants();
dvLoanParticipants.setPartyId(Long.valueOf(partyId));
dvLoanParticipants.setDvpParticipantName("Builder");
dvLoanParticipants.setDvpParticipantType("Individual");
Party party = new Party();
Map<String, DVLoanParticipants> dvLoanParticipantsMap = new
java.util.HashMap<>();
dvLoanParticipantsMap.put("Builder", dvLoanParticipants);
party.setPartyId(Long.valueOf(partyId));
party.setDvLoanParticipantsMap(dvLoanParticipantsMap);
repository.save(party);
What is the mistake i am doing ?
The root cause of your problem in this part:
#OneToMany(targetEntity = DVLoanParticipants.class,cascade = CascadeType.ALL)
#JoinColumn(name = "LOAN_ID")
#MapKey(name="dvpParticipantName")
private Map<String, DVLoanParticipants> dvLoanParticipantsMap;
actually for your case the column name in the #JoinColumn means:
If the join is for a unidirectional OneToMany mapping using a foreign key mapping strategy, the foreign key is in the table of the target entity.
So, assuming for the clarity that you want to map the following schema:
create table PARTY
(
PARTY_ID int,
-- ...
primary key (PARTY_ID)
);
create table DV_LOAN_PARTICIPANTS
(
PARTY_ID int,
DVP_PARTICIPANT_NAME varchar(50),
DVP_PARTICIPANT_TYPE varchar(10),
-- ...
primary key (PARTY_ID, DVP_PARTICIPANT_NAME),
foreign key (PARTY_ID) references PARTY(PARTY_ID)
);
You can use the following mapping:
#Entity
#Table(name = "PARTY")
public class Party
{
#Id
#Column(name = "PARTY_ID")
private Long partyId;
// I use fetch = FetchType.EAGER instead of deprecated #LazyCollection(LazyCollectionOption.FALSE)
// targetEntity = DVLoanParticipants.class is redundant here
#OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
#JoinColumn(name = "PARTY_ID") // this is DV_LOAN_PARTICIPANTS.PARTY_ID column
#MapKey(name = "dvpParticipantName")
private Map<String, DVLoanParticipants> dvLoanParticipantsMap;
public Party()
{
dvLoanParticipantsMap = new HashMap<>();
}
// getters / setters
public void addParticipant(DVLoanParticipants p)
{
this.dvLoanParticipantsMap.put(p.getDvpParticipantName(), p);
p.setPartyId(getPartyId());
}
}
#Entity
#Table(name = "DV_LOAN_PARTICIPANTS")
public class DVLoanParticipants implements Serializable
{
#Id
#Column(name = "PARTY_ID")
private Long partyId;
#Id
#Column(name = "DVP_PARTICIPANT_NAME")
private String dvpParticipantName;
#Column(name = "DVP_PARTICIPANT_TYPE")
private String dvpParticipantType;
// getters / setters
}
and example how to save:
Party party = new Party();
party.setPartyId(2L);
// ...
DVLoanParticipants part1 = new DVLoanParticipants();
part1.setDvpParticipantName("Name 3");
part1.setDvpParticipantType("T1");
DVLoanParticipants part2 = new DVLoanParticipants();
part2.setDvpParticipantName("Name 4");
part2.setDvpParticipantType("T1");
party.addParticipant(part1);
party.addParticipant(part2);
repository.save(party);
and several notes:
The LazyCollectionOption.TRUE and LazyCollectionOption.FALSE values are deprecated since you should be using the JPA FetchType attribute of the #OneToMany association.
You use hibernate specific approach for mapping сomposite identifiers. As it's mentioned in the hibernate documentation:
The restriction that a composite identifier has to be represented by a primary key class (e.g. #EmbeddedId or #IdClass) is only JPA-specific.
Hibernate does allow composite identifiers to be defined without a primary key class via multiple #Id attributes.
But if you want to achieve more portability you should prefer one of the jpa allowed approaches.
I have 2 tables namely user & user_session.
User table has user_id as a primary key which is referrers to user_session table.
Plus user_session has composite key including session_intime and user_id.
I have designed my entity in JPA. Now I want to map these two entities. I have tried to map these two tables. But my application build failed. Can you please help me out?
#Entity
#Table(name="user")
public class User {
#Id
#Email
#Column(name = "user_id")
private String userId;
#Column(name = "password")
private String password;
#Column(name = "fname")
private String fname;
#OneToMany(fetch = FetchType.LAZY)
#JoinColumn(name = "userId", referencedColumnName = "user_id")
private UserSession userSession;
}
#Entity
#Table(name="user_session")
public class UserSession{
#EmbeddedId
private UserSessionPK userSessionPK;
#Column(name = "remote_ip")
private String remoteIp;
}
#Embeddable
public class UserSessionPK implements Serializable {
private static final long serialVersionUID = 1L;
#Column(name = "user_id")
private String userId;
#Temporal(TemporalType.TIMESTAMP)
#Column(name = "time_in")
private Date timeIn;
}
I want to map user_id of User table to user_id of UserSessionPK. I am new to JPA, so I don't know how to map with embeddable class.
Remove the mappedBy attribute. This attribute is used when you have bidirectional relationship to indicate which side of the relationship is the owner.
But you will need to set the Foreign Key aka JoinColumn
#JoinColumn("user_id")
#OneToMany(fetch = FetchType.LAZY)
private UserSession userSession;