Question

我是Hybernate的新手，很抱歉，如果它是愚蠢的问题。当我运行JUnit Test时，我看到了这个错误：

could not execute query; SQL [select employee0_.id_employee as id_emplo1_5_, employee0_.date_of_birth as date_of_2_5_, employee0_.id_department as id_depar9_5_, employee0_.email as email3_5_, employee0_.home_phone as home_pho4_5_, employee0_.mobile_phone as mobile_p5_5_, employee0_.name as name6_5_, employee0_.pesel as pesel7_5_, employee0_.surname as surname8_5_ from employee employee0_]; nested exception is org.hibernate.exception.SQLGrammarException: could not execute query

Hibernate在查询中添加了一些“0_”？我在mysql db中有这些列。

我的员工DAO有：

    public List<Employee> findEmployeeByDepartmentName(String name) {
        TypedQuery<Employee> query = entityManager.createQuery(
                "select e from Employee e join e.department  d where d.name = :name",
                Employee.class);
        query.setParameter("name", name);

        return query.getResultList();
    }

和员工：

package com.capgemini.domain;

import java.io.Serializable;

//更多导入......

@Entity
@Table(name = "EMPLOYEE")
public class Employee implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long idEmployee;

    @Column(nullable = true, length = 30)
    private String name;

    @Column(nullable = true, length = 30)
    private String surname;

    @Column(nullable = false, length = 11)
    private BigInteger pesel;

    @Column(nullable = false, length = 10, columnDefinition = "DATE")
    private LocalDate dateOfBirth;

    @Column(nullable = false, length = 40)
    private String email;

    @Column(nullable = false, precision = 10)
    private BigDecimal homePhone;

    @Column(nullable = false, precision = 9)
    private BigDecimal mobilePhone;

    public Employee() {
        super();
    }

    public static long getSerialversionuid() {
        return serialVersionUID;
    }
//more getters....

    public void setIdEmployee(Long idEmployee) {
        this.idEmployee = idEmployee;
    }
//more setters...


}

这种侵蚀的原因是什么？我尽可能地简化了我的问题。

Answer 1

不要担心Hibernate为查询添加的额外内容，这些只是它自动生成的别名（并且数字确保它们是唯一的）。

您的查询不正确，因此请在此处查找错误：

select e from Employee e join e.department  d where d.name = :name

请记住，这不是SQL，而是HQL，这是微妙的不同。

我注意到的第一件事是Employee类没有名为department的字段，所以我先检查一下。

Answer 2

我好极了！我粘贴了wronge方法/代码：

@Override
public List<Employee> findEmployeeByName(String name) {
    TypedQuery<Employee> query = entityManager.createQuery(
            "SELECT e FROM Employee e where e.name like :name",
            Employee.class);
    query.setParameter("name", name);

    return query.getResultList();
}

和Eroor：

org.springframework.dao.InvalidDataAccessResourceUsageException: could not execute query; SQL [select employee0_.id_employee as id_emplo1_5_, employee0_.date_of_birth as date_of_2_5_, employee0_.id_department as id_depar9_5_, employee0_.email as email3_5_, employee0_.home_phone as home_pho4_5_, employee0_.mobile_phone as mobile_p5_5_, employee0_.name as name6_5_, employee0_.pesel as pesel7_5_, employee0_.surname as surname8_5_ from employee employee0_ where employee0_.name like ?]; nested exception is org.hibernate.exception.SQLGrammarException: could not execute query

即使我简化它：

@Override
public List<Employee> findEmployeeByName(String name) {
    TypedQuery<Employee> query = entityManager.createQuery(
            "SELECT e FROM Employee e",
            Employee.class);
    query.setParameter("name", name);

    return query.getResultList();
}

错误是：

org.springframework.dao.InvalidDataAccessResourceUsageException: could not execute query; SQL [select employee0_.id_employee as id_emplo1_5_, employee0_.date_of_birth as date_of_2_5_, employee0_.id_department as id_depar9_5_, employee0_.email as email3_5_, employee0_.home_phone as home_pho4_5_, employee0_.mobile_phone as mobile_p5_5_, employee0_.name as name6_5_, employee0_.pesel as pesel7_5_, employee0_.surname as surname8_5_ from employee employee0_ where employee0_.name like ?]; nested exception is org.hibernate.exception.SQLGrammarException: could not execute query

我在Workbench中执行了这个查询（删除0_），它正在运行：

use mytestdb;
select employee.id_employee as id_emplo1_5_, employee.date_of_birth as date_of_2_5_, employee.id_department as id_depar9_5_, employee.email as email3_5_, employee.home_phone as home_pho4_5_, employee.mobile_phone as mobile_p5_5_, employee.name as name6_5_, employee.pesel as pesel7_5_, employee.surname as surname8_5_ from employee employee

Answer 3

我发现如果我改变了

@Column(name = "dateOfBirth", nullable = false, length = 10, columnDefinition = "DATE")
private LocalDate dateOfBirth;

到

@Column(name = "dateOfBirth", nullable = false, length = 10, columnDefinition = "DATE")
private Date dateOfBirth;

然后它正在工作！为什么？我该如何解决？

嵌套异常是org.hibernate.exception.SQLGrammarException：无法执行查询 - 添加了“0_”

3 个答案: