Could not determine type for entity in JPA

Question

I'm following a JPA/Hibernate course from UDemy (https://www.udemy.com/course/hibernate-and-spring-data-jpa-beginner-to-guru) and was asked to convert a FKEY long identifier into object it points to on the entity class. Things worked before doing this. Now I get that

Caused by: org.hibernate.MappingException: Could not determine type for: com.guru.sdjpajdbc.domain.Author, at table: book, for columns: [org.hibernate.mapping.Column(author)]

error.

package com.guru.sdjpajdbc.domain;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.NoArgsConstructor;

@Data
@Entity
@Builder
@NoArgsConstructor
@AllArgsConstructor
@EqualsAndHashCode
public class Author {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @EqualsAndHashCode.Exclude  String firstName;

    @EqualsAndHashCode.Exclude private String lastName;

}

package com.guru.sdjpajdbc.domain;


import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

import org.springframework.data.annotation.Transient;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@Entity
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class Book {
    public Book(String isbn, String publisher, String title) {
        super();
        this.isbn = isbn;
        this.publisher = publisher;
        this.title = title;
    }

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String isbn;

    private String publisher;

    private String title;

    @Transient
    private Author author;

}

V1__init_database.sql

drop table if exists book cascade;
drop table if exists author;

create table book (id        bigint not null auto_increment primary key,isbn      varchar(255),publisher varchar(255),title     varchar(255),author_id BIGINT) engine = InnoDB;

create table author
(
    id         bigint not null auto_increment primary key,
    first_name varchar(255),
    last_name  varchar(255)
) engine = InnoDB;

alter table book
    add constraint book_author_fk foreign key (author_id) references author (id);

insert into author (first_name, last_name) values ('Craig', 'Walls');

insert into book (isbn, publisher, title, author_id) values ('978-1617294945', 'Simon & Schuster',
       'Spring in Action, 5th Edition',(select id from author where first_name = 'Craig' and last_name = 'Walls') );

insert into book (isbn, publisher, title, author_id) values ('978-1617292545', 'Simon & Schuster',
    'Spring Boot in Action, 1st Edition',(select id from author where first_name = 'Craig' and last_name = 'Walls') );

insert into book (isbn, publisher, title, author_id) values ('978-1617297571', 'Simon & Schuster',
    'Spring in Action, 6th Edition',(select id from author where first_name = 'Craig' and last_name = 'Walls') );

insert into author (first_name, last_name) values ('Eric', 'Evans');

insert into book (isbn, publisher, title, author_id) values ('978-0321125217', 'Addison Wesley',
    'Domain-Driven Design',(select id from author where first_name = 'Eric' and last_name = 'Evans') );

insert into author (first_name, last_name) values ('Robert', 'Martin');

insert into book (isbn, publisher, title, author_id) values ('978-0134494166', 'Addison Wesley',
    'Clean Code',(select id from author where first_name = 'Robert' and last_name = 'Martin') );

The instructor ran into this error but fixed it solely by adding the @Transient annotation. For some reason, it works for him, but not for me.

Could not determine type for entity in JPA

0 Answers