CODEWITHSUNDEEP
javasqlspringhibernate
F___
F___

Reputation: 139

hibernate relationship can't found foreign key on annotation way

I'm new to hibernate try lean hibernate relationship and have tow table, relationship is one to many

  create table student(
    id bigint primary key auto_increment,
    name varchar(20),
    student_class_id bigint foreign key references student_class(id)
  )

  create table student_class(
    id bigint primary key auto_increment,
    name varchar(20)
  )

spring sessionFactory bean have configured packageToScan entity

this is entity class:

@Table(name = "students")
@Entity
public class Student {
    private Integer id;
    private Integer name;
    private StudentClass studentClass;

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    @Column(name = "name")
    public Integer getName() {
        return name;
    }

    public void setName(Integer name) {
        this.name = name;
    }

    @OneToOne
    @JoinColumn(name = "student_class_id")
    @Cascade(org.hibernate.annotations.CascadeType.SAVE_UPDATE)
    public StudentClass getStudentClass() {
        return studentClass;
    }
    // setter getter
}


@Entity
@Table(name = "student_class")
public class StudentClass {
    private Integer id;
    private String name;
    private Set<Student> students = new HashSet<Student>();

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    @Column(name = "name")
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Cascade(org.hibernate.annotations.CascadeType.SAVE_UPDATE)
    @OneToMany(mappedBy = "studentClass", cascade = {CascadeType.ALL}, fetch = FetchType.EAGER)
    public Set<Student> getStudents() {
        return students;
    }
    /setter getter
}

sql is: select sc.name from StudentClass sc left join Student s on sc.id = s.student_class_id

and junit test fount error

[DEBUG] 2018-05-26 11:59:39.993 [main] HqlSqlBaseWalker - select << begin [level=1, statement=select]
[DEBUG] 2018-05-26 11:59:40.005 [main] FromElement - FromClause{level=1} : com.f.pojo.StudentClass (sc) -> studentcla0_
[DEBUG] 2018-05-26 11:59:40.009 [main] HqlSqlWalker - Creating entity-join FromElement [s -> com.f.pojo.Student]
[DEBUG] 2018-05-26 11:59:40.010 [main] FromElement - FromClause{level=1} : com.f.pojo.Student (s) -> student1_
[DEBUG] 2018-05-26 11:59:40.012 [main] FromReferenceNode - Resolved : sc -> studentcla0_.id
[DEBUG] 2018-05-26 11:59:40.013 [main] DotNode - getDataType() : id -> org.hibernate.type.IntegerType@26a2f7f9
[DEBUG] 2018-05-26 11:59:40.013 [main] FromReferenceNode - Resolved : sc.id -> studentcla0_.id
[DEBUG] 2018-05-26 11:59:40.013 [main] FromReferenceNode - Resolved : s -> student1_.id
[ERROR] 2018-05-26 11:59:40.016 [main] ErrorTracker -  could not resolve property: student_class_id of: com.f.pojo.Student
[ERROR] 2018-05-26 11:59:40.016 [main] ErrorTracker -  could not resolve property: student_class_id of: com.f.pojo.Studentcker -  could not resolve property: student_class_id of: com.f.pojo.Student
java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: could not resolve property: student_class_id of: com.f.pojo.Student [select sc.name from com.f.pojo.StudentClass sc left join com.f.pojo.Student s on sc.id = s.student_class_id]

I'm two entity relationship seem be right, student entity using studentClass property references studentClass entity

Upvotes: 0

Views: 136

Answers (1)

Guilherme Mussi
Guilherme Mussi

Reputation: 1057

Your SQL:

create table student(

Your class:

@Table(name = "students")

These names need to match. Even a single character (s) makes a big difference.

Another problem in your SQL:

name varchar(20),

Your class:

private Integer name;

The type also needs to match. I believe you meant to use String in your class instead of Integer.

Upvotes: 1

Related Questions