Question

我创建了hbm2dll的演示应用程序作为create（也尝试使用create-drop） EMployee类将ID作为主键，GenerateType为AUTO。电子邮件字段是唯一且无效的。

我收到以下异常。

Hibernate: call next value for hibernate_sequence
Hibernate: insert into Employee (EMAIL, FIRST_NAME, LAST_NAME, ID) values (?, ?, ?, ?)
Apr 06, 2017 9:19:57 AM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
WARN: SQL Error: 23505, SQLState: 23505
Apr 06, 2017 9:19:57 AM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
**ERROR: Unique index or primary key violation: "UK_ARDF0F11MFA6TUJS3HFLTHWDV_INDEX_7 ON PUBLIC.EMPLOYEE(EMAIL) VALUES ('demo-user2@mail.com', 8)"; SQL statement:**
insert into Employee (EMAIL, FIRST_NAME, LAST_NAME, ID) values (?, ?, ?, ?) [23505-194]
Apr 06, 2017 9:19:57 AM org.hibernate.engine.jdbc.batch.internal.AbstractBatchImpl release
INFO: HHH000010: On release of batch it still contained JDBC statements
Apr 06, 2017 9:19:57 AM org.hibernate.internal.ExceptionMapperStandardImpl mapManagedFlushFailure
ERROR: HHH000346: Error during managed flush [org.hibernate.exception.ConstraintViolationException: could not execute statement]

的hibernate.cfg.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="hibernate.connection.driver_class">org.h2.Driver</property>
        <property name="hibernate.connection.url">jdbc:h2:tcp://localhost/~/test</property>
        <property name="hibernate.connection.password"></property>
        <property name="hibernate.connection.username">sa</property>
        <property name="hibernate.dialect">org.hibernate.dialect.H2Dialect</property>
        <property name="show_sql">true</property>
        <property name="hibernate.hbm2ddl.auto">create</property>
        <mapping class="EmployeeEntity"></mapping>
    </session-factory>
</hibernate-configuration>

员工CLass

@Entity
@Table(name = "Employee", uniqueConstraints = {
        @UniqueConstraint(columnNames = "EMAIL") })
public class EmployeeEntity implements Serializable {

    private static final long serialVersionUID = -1798070786993154676L;

    @Id
    private int employeeId;
    @Transient
    private Address address;

    @Column(name = "EMAIL", unique = true, nullable = false, length = 100)
    private String email;

    @Column(name = "FIRST_NAME", unique = false, nullable = false, length = 100)
    private String firstName;

    @Column(name = "LAST_NAME", unique = false, nullable = false, length = 100)
    private String lastName;

    public int getEmployeeId() {
        return employeeId;
    }

    public void setEmployeeId(int employeeId) {
        this.employeeId = employeeId;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

}

Answer 1

您的代码中存在以下原因导致ConstraintViolationException：

1：默认策略是在hibernate中assigned确保你没有分配重复的id，如果你想让hibernate / JPA为你处理id生成那么你应该添加@GeneratedValue`注释，它默认值为id AUTO增量。您可以根据自己的要求进行更改。

  @Id
        @GeneratedValue
        private int employeeId;

2：确保您没有向2个不同的对象提供重复的电子邮件地址并保存。

3：firstName，lastName不能为null

hbm2ddl.auto创建属性不起作用

1 个答案: