java - 插入数据的唯一约束错误

Question

我收到奇怪的错误，原因是:

java.sql.SQLIntegrityConstraintViolationException: ORA-00001: unique constraint

执行以下代码时:

Product DAO.java

@Id
@Column(name = "no", columnDefinition = "NUMBER")
private int serial_number;
//No getter and setter for this field

@Column(name = "fname", columnDefinition = "VARCHAR2(50)")
private int fname;

@Column(name = "lname", columnDefinition = "VARCHAR2(50)")
private int lname;
// Getter and setter for fname and lname


ProductService.java

Product po = new Product();
po.setfname = "Tom";
po.setlname = "John";
//I am not setting 'no' field value since I have created sequence in my oracle table to auto increment the value. 

当我运行此代码时，我在字段“no”上收到唯一约束错误。任何人都可以帮助我确定我在代码中做错了什么。当我已经在表中为“否”字段创建了序列时，我是否需要在配置文件或代码中进行任何更改？由于它是生产数据库，我也不知道序列名称。

hibernate-cgf.xml
<hibernate-configuration>
    <session-factory>
        <property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="hibernate.connection.url">jdbc:oracle:thin:@localhost:1521:xe</property>
        <property name="hibernate.connection.password">pass</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.dialect">org.hibernate.dialect.OracleDialect</property>
        <property name="show_sql">true</property>
        <property name="hbm2ddl.auto">update</property>
        <mapping class="dao.Product"></mapping>
    </session-factory>
</hibernate-configuration>

Answer 1

您的 id 字段 serial_number 是一个初始化为零的 int，并且 @Id 的映射不包含 @GenerateValue 注释，因此 hibernate 将假定您正在手动分配 id 并保存它每次持久化对象时都将其设置为零，从而导致 SQLIntegrityConstraintViolationException。您需要添加 @GenerateValue 注解，您还可以选择策略，如下所示:

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "no", columnDefinition = "NUMBER")
private int serial_number;