英文:
Constantly getting org.hibernate.AnnotationException: @OneToOne or @ManyToOne references an unknown entity: error
问题
我可以成功地通过Db2控制台将记录插入到表中。
INSERT INTO db2admin.school VALUES (1, 'BJS');INSERT INTO db2admin.STUDENT VALUES (1, 'Pankaj', 30, 1);
我有以下的表。
CREATE TABLE DB2ADMIN.School (school_id SMALLINT PRIMARY KEY NOT NULL, name varchar(128));CREATE TABLE DB2ADMIN.Student (student_id int PRIMARY KEY NOT NULL, name varchar(128) NOT NULL, age smallint NOT NULL, school_id int NOT NULL, FOREIGN KEY (school_id) REFERENCES School(school_id));
一个学校可以包含许多学生。以下是我在Hibernate 5.4.18中如何定义实体关系。
@Entity@Table(name = "school")public class School {@Id@SequenceGenerator(name = "SchoolIdSequence", schema = "db2admin", sequenceName = "Sequence_School", allocationSize = 1)@GeneratedValue(generator = "SchoolIdSequence", strategy = GenerationType.SEQUENCE)@Column(name = "SCHOOL_ID")private int id;@Column(name = "NAME")private String name;@OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, mappedBy = "school")//@JoinColumn(name = "student_id", nullable = false)private Set<Student> students;public School() {}public School(String name) {this.name = name;}// ... 省略其他方法和属性的定义}@Entity@Table(name = "student")public class Student {@Id@SequenceGenerator(name = "SequenceStudentId", sequenceName = "Sequence_Student", allocationSize = 1)@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SequenceStudentId")@Column(name = "STUDENT_ID")private int id;@Column(name = "NAME")private String name;@Column(name = "AGE")private int age;@ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY)@JoinColumn(name = "school_id", nullable = false)private School school;public Student() {}public Student(String name, int age, School school) {this.name = name;this.age = age;this.school = school;}// ... 省略其他方法和属性的定义}
在执行应用程序时，我收到以下错误。
org.hibernate.AnnotationException: @OneToOne or @ManyToOne on org.jfa.persistence.hibernate.entity.Student.school references an unknown entity: org.jfa.persistence.hibernate.entity.School
我已经尝试根据Internet/StackOverflow上其他人的建议以不同的方式调整类中的关系设置。然而，到目前为止还没有成功。请帮忙解决。
英文:
I can successfully insert records into the tables using the Db2 console.
INSERT INTO db2admin.school VALUES (1, 'BJS');INSERT INTO db2admin.STUDENT VALUES (1, 'Pankaj', 30, 1);
I have the following tables.
CREATE TABLE DB2ADMIN.School (school_id SMALLINT PRIMARY KEY NOT NULL, name varchar(128));create table DB2ADMIN.Student (student_id int PRIMARY KEY NOT null, name varchar(128) not null, age smallint not null, school_id int NOT NULL, FOREIGN KEY (school_id) REFERENCES School(school_id));
One School can contain many students. Here is how I am defining the entity relationships in Hibernate 5.4.18.
@Entity@Table(name = "school")public class School{@Id@SequenceGenerator(name = "SchoolIdSequence", schema="db2admin", sequenceName = "Sequence_School", allocationSize = 1)@GeneratedValue(generator = "SchoolIdSequence", strategy = GenerationType.SEQUENCE)@Column(name = "SCHOOL_ID")private int id;@Column(name = "NAME")private String name;@OneToMany(fetch = FetchType.LAZY, cascade=CascadeType.ALL, mappedBy = "school")//@JoinColumn(name="student_id", nullable=false)private Set<Student> students;public School(){}public School(String name){this.name = name;}public int getId(){return id;}public void setId(int id){this.id = id;}public String getName(){return name;}public void setName(String name){this.name = name;}public Set getStudents(){return students;}public void setStudents(Set students){this.students = students;}@Overridepublic String toString(){return "School [Name = '" + name + "']";}}@Entity@Table(name = "student")public class Student{@Id@SequenceGenerator(name = "SequenceStudentId", sequenceName = "Sequence_Student", allocationSize = 1)@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SequenceStudentId")@Column(name = "STUDENT_ID")private int id;@Column(name = "NAME")private String name;@Column(name = "AGE")private int age;@ManyToOne(cascade=CascadeType.ALL, fetch = FetchType.LAZY)@JoinColumn(name="school_id", nullable=false)private School school;public Student(){}public Student(String name, int age, School school){this.name = name;this.age = age;this.school = school;}public int getId(){return id;}public void setId(int id){this.id = id;}public String getName(){return name;}public void setName(String name){this.name = name;}public int getAge(){return age;}public void setAge(int age){this.age = age;}@Overridepublic String toString(){return "Student [id=" + id + ", Name=" + name + ", Age=" + age + "]";}}
I get the following error on executing the application.
org.hibernate.AnnotationException: @OneToOne or @ManyToOne on org.jfa.persistence.hibernate.entity.Student.school references an unknown entity: org.jfa.persistence.hibernate.entity.School
I have tried to tweak the relationship settings in the class in different ways as suggested by others on Internet/StackOverFlow. Yet, no luck so far. Please help.
答案1
得分: 0
你在 School.java 中错误地引用了 school_id，而不是 student_id。应该是：
class School{...@OneToMany(fetch = FetchType.LAZY, cascade=CascadeType.ALL)@JoinColumn(name="student_id", nullable=false)private Set<Student> students;...}
英文:
You have wrongly referenced school_id instead of student_id in School.java. It should be:
class School{...@OneToMany(fetch = FetchType.LAZY, cascade=CascadeType.ALL)@JoinColumn(name="student_id", nullable=false)private Set<Student> students;...}
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