6

我是 Java 编程新手。我的班级中有一个枚举数据类型：

public class Persons {
    private String name;
    private String family;
    private Date birthDate;
    public enum degree {Bsd, Msd, prof};
    private degree degree;
    ...
}

在我的 MySQL 数据库中，我有一个学位字段：ENUM('Bsd','Mds','prof')我的休眠映射是这样的：

<class name="Entity.Professor" table="tbl_professor">
     <id column="ProfessorId" name="ProfessorId"/>
     <property column="name" name="name"/>
     <property column="family" name="family"/>
     <property column="birthDate" name="birthDate"/>
     <property column="degree" name="degree"/>
</class>

当我想在我的表中插入一条新记录时，我收到了这个错误：

Hibernate: insert into tbl_professor (name, family, birthDate, degree, ProfessorId) values (?, ?, ?, ?, ?)
Apr 26, 2013 6:15:24 PM org.hibernate.util.JDBCExceptionReporter logExceptions
WARNING: SQL Error: 1265, SQLState: 01000
Apr 26, 2013 6:15:24 PM org.hibernate.util.JDBCExceptionReporter logExceptions
SEVERE: Data truncated for column 'degree' at row 1
Apr 26, 2013 6:15:24 PM org.hibernate.event.def.AbstractFlushingEventListener performExecutions
SEVERE: Could not synchronize database state with session
org.hibernate.exception.GenericJDBCException: Could not execute JDBC batch update
    at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
    at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:253)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:237)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:141)
    at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)
    at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
    at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
    at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338)
    at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
    at DAO.ProfessorDAO.createProfessor(ProfessorDAO.java:21)
    at Entity.Test.main(Test.java:39)
Caused by: java.sql.BatchUpdateException: Data truncated for column 'degree' at row 1
    at com.mysql.jdbc.PreparedStatement.executeBatchSerially(PreparedStatement.java:2028)
    at com.mysql.jdbc.PreparedStatement.executeBatch(PreparedStatement.java:1451)
    at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:48)
    at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:246)
    ... 9 more
Caused by: java.sql.SQLException: Data truncated for column 'degree' at row 1
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3609)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3541)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2002)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2163)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2624)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2127)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2427)
    at com.mysql.jdbc.PreparedStatement.executeBatchSerially(PreparedStatement.java:1980)
    ... 12 more

Exception in thread "main" org.hibernate.exception.GenericJDBCException: Could not execute JDBC batch update
    at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
    at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:253)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:237)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:141)

谁能帮我？我真的对enum数据类型感到困惑。

4

4 回答 4

8

数据截断是当您添加的记录长于数据库列的最大列大小（在您的情况下degree）。

由于您的 DEGREE 列的 MySQL ENUM 有 3 种类型，您可以使用@Enumerated如下注释您的枚举：

@Enumerated(EnumType.STRING)
private degree degree;
于 2013-04-26T14:28:13.933 回答
2

你需要在hibernate中以不同的方式映射枚举，Hibernate提供了org.hibernate.type.EnumType来映射枚举类型

   <property name="degree">
      <type name="org.hibernate.type.EnumType">
         <param name="enumClass">pkg.degree</param>
      </type>
   </property>

如果要存储字符串而不是索引 1,2 等，则需要使用 12

12 - java.sql.Types.VARCHAR

查看链接 Hibernate map enum to varchar

于 2013-04-26T14:31:52.930 回答
1

那么你得到一个数据截断错误，所以我会检查你的 MySQL 列的允许长度。通常，如果该字段中的数据大于您的 Hibernate/JPA 映射或允许的 db 列的长度，您会看到此错误。

于 2013-04-26T14:28:06.307 回答
0

一种解决方案是不使用枚举类型的mysql。另一种选择是纯字符串，甚至更好的是带有 id 作为关系的额外表。

它有几个缺点。主要是维护它。您不能轻易更改订单或删除其中的内容

如果您使用 google 搜索 mysql，则此页面排名第三是有原因的：http: //komlenic.com/244/8-reasons-why-mysqls-enum-data-type-is-evil/

于 2017-10-05T12:49:04.023 回答