引起：java.sql.SQLException：未找到列“id”
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Caused by: java.sql.SQLException: Column 'id' not found
提问by quento
I want to get some fields and then set it to my Test.entity. My SQL query:
我想获取一些字段，然后将其设置为我的 Test.entity。我的 SQL 查询：
query = "SELECT t.id as tId, t.test_name, t.duration, q.id as qId, " +
"q.question as question, q.is_multichoice as is_multichoice, " +
"q.is_open as is_open, a.id as aId, a.answer_text as answer_text FROM result r " +
"JOIN test t ON r.test_id = t.id " +
"JOIN user u ON r.user_id = u.id " +
"JOIN question q ON t.id = q.test_id JOIN answer a ON q.id = a.question_id " +
"WHERE t.id = :testId AND u.id = :userId AND r.permission = :permissionId " +
"AND q.archived = false AND a.archived = false", resultClass = com.bionic.entities.Test.class)
Test Entity:
测试实体：
public class Test {
@Id
@Column(name = "id")
@GeneratedValue(strategy = GenerationType.AUTO)
private long id;
@Column(name = "duration", nullable = false)
private int duration;
@Column(name = "test_name", nullable = false, unique = true)
private String testName;
@Column(name = "archived", nullable = false)
private boolean archived;
@OneToMany(mappedBy = "test", fetch = FetchType.EAGER)
private Set<Question> questions;
@ManyToMany(mappedBy = "tests")
private Set<User> users;
Question Entity:
问题实体：
public class Question {
@Id
@Column(name = "id")
@GeneratedValue(strategy = GenerationType.AUTO)
private long id;
@Column(name = "is_multichoice", nullable = false)
private boolean isMultichoice;
@Column(name = "is_open", nullable = false)
private boolean isOpen;
@Column(name = "picture")
private String picture;
@Column(name = "question")
private String question;
@ManyToOne
@JoinColumn(name = "test_id", nullable = false)
private Test test;
@Column(name = "archived", nullable = false)
private boolean isArchived;
@OneToMany(mappedBy = "question", fetch = FetchType.EAGER)
private Set<Answer> answers;
Answer Entity:
回答实体：
public class Answer {
@Id
@Column(name = "id")
@GeneratedValue(strategy = GenerationType.AUTO)
private long id;
@Column(name = "answer_text", nullable = false)
private String answerText;
@Column(name = "mark", nullable = false)
private int mark;
@ManyToOne
@JoinColumn(name = "question_id")
private Question question;
@Column(name = "picture")
private String picture;
@Column(name = "archived", nullable = false)
private boolean isArchived;
However, after executing this query i am getting exeption :
但是，在执行此查询后，我得到了例外：
Caused by: java.sql.SQLException: Column 'id' not found.
DAO.class:
DAO.class:
public Test getCurrentTest(long id, long testId, long permissionId) {
Query query = em.createNamedQuery("getCurrentTestById");
query.setParameter("userId", id);
query.setParameter("testId", testId);
query.setParameter("permissionId", permissionId);
return (Test) query.getSingleResult();
}
What am i doing wrong?
我究竟做错了什么？
回答by Rabbit
Your query doesn't return a field named id. It has fields named aId, qId, and tId.
您的查询不会返回名为 的字段id。它有名为 的字段aId, qId, and tId。
You need to use the correct column names in your entities. For example, in your Test entity, you declared a column named id. Except your query doesn't return a column named id, it returns a column named tId. See below for an example of what needs to be changed.
您需要在实体中使用正确的列名称。例如，在您的 Test 实体中，您声明了一个名为 id 的列。除了您的查询不返回名为 id 的列之外，它返回名为 tId 的列。有关需要更改的内容的示例，请参见下文。
public class Test {
@tId
@Column(name = "tId")
@GeneratedValue(strategy = GenerationType.AUTO)
private long tId;
....
