Question

我有两个实体--Group和UserGroup，它们与groupId连接。＆＃34; \＆＃34;是因为postgre区分大小写，这样我们就可以纠正这个事实。

@Entity
@Table(name = "\"Group\"")
public class Group {

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "\"groupId\"")
private int groupId;

@Column(name = "\"groupName\"")
private String groupName;

@OneToMany(mappedBy = "group")
List<Project> projects;

@OneToMany(mappedBy = "group")
private List<UserGroup> members;


public Group(String groupName) {
    this.groupName = groupName;
}

public Group() {
}

public int getGroupId() {
    return groupId;
}

public void setGroupId(int groupId) {
    this.groupId = groupId;
}
public String getGroupName() {
    return groupName;
}

public void setGroupName(String groupName) {
    this.groupName = groupName;
}

public List<Project> getProjects() {
    return projects;
}

public void setProjects(List<Project> projects) {
    this.projects = projects;
}

public List<UserGroup> getMembers() {
    return members;
}
public void setMembers(List<UserGroup> members) {
    this.members = members;
}

@Override
public String toString() {
    return "Group{" +
            "groupId=" + groupId +
            ", groupName='" + groupName + '\'' +
            '}';
}

}

和UserGroup

@Entity
@Table(name = "\"UserGroup\"")
@IdClass(GroupAssociationId.class)
public class UserGroup {

@Id
@Column(name = "\"userId\"")
private int userId;
@Id
@Column(name = "\"groupId\"")
private int groupId;

@ManyToOne
@PrimaryKeyJoinColumn(name = "\"userId\"", referencedColumnName = "\"userId\"")
private User member;

@ManyToOne
@PrimaryKeyJoinColumn(name = "\"groupId\"", referencedColumnName = "\"groupId\"")
private Group group;

@ManyToOne
@JoinColumn(name = "\"accessId\"")
private Access access;

public UserGroup(Group group, User member, Access access) {
    this.group = group;
    this.member = member;
    this.access = access;
}

public UserGroup() {
}

public int getUserId() {
    return userId;
}

public void setUserId(int userId) {
    this.userId = userId;
}

public int getGroupId() {
    return groupId;
}

public void setGroupId(int groupId) {
    this.groupId = groupId;
}

public User getMember() {
    return member;
}

public void setMember(User member) {
    this.member = member;
}

public Group getGroup() {
    return group;
}

public void setGroup(Group group) {
    this.group = group;
}

public Access getAccess() {
    return access;
}

public void setAccess(Access access) {
    this.access = access;
}

@Override
public String toString() {
    return "UserGroup{" +
            "userId=" + userId +
            ", groupId=" + groupId +
            ", access=" + access.getAccessName() +
            '}';
}
}

当我尝试在表UserGroup中创建一行时出错：

引起：org.postgresql.util.PSQLException：错误：列＆＃34; group_groupId＆＃34;关系＆＃34; UserGroup＆＃34;不存在

为什么呢？这发生在字符串＆＃34; em.getTransaction（）。commit（）上。真的很奇怪。

Answer 1

在UserGroup表中，有一列：

 "group_`groupId`"

已生成（因为您正在使用＆＃34;＆＃34;以保持区分大小写。

您可以在postgres中编辑列的名称（以及foreing键）：

"group_`groupId`"   --->   "group_groupId"

JPA正在寻找group_groupId。

Answer 2

我设法回答了这个问题。问题在于序列生成。在嵌入式数据库中生成时，我不知道为什么，生成类型序列不起作用。相反，我使用了Identity类型，一切都开始工作了

变量的名称将添加到列的名称中

2 个答案: