MySQL / Hibernate：非空列的默认值不起作用 [英] MySQL/Hibernate : Default value for not-null column does not work

问题描述

  org.hibernate.PropertyValueException：非空属性引用
空值或瞬态值
  

我使用Java，Hibernate和MySQL 5.1.52-log版本。

我对默认的解释是如果我不' t为列提供值，当我尝试保存这个对象时，Hibernate会插入默认值。

HBM文件，

 < property name =isActivetype =java.lang.Short> 
< column name =IsActivenot-null =truedefault =1/> 
< / property> 
  

解决方案

根据PropertyValueException的文档，如果设置在一个声明为not-null =true的属性中使用null值，然后尝试持久化/更新它，然后你会得到这个异常。

参见 http://docs.jboss.org/hibernate/orm/3.5/javadoc/ org / hibernate / PropertyValueException.html

您应该从配置中删除not-null =true属性（因为not-null的默认值是假的），然后数据库应该插入您在配置中为您指定的默认值（在本例中为'1'）。

[UPDATE]

我宁愿将此作为对fujy答案的评论，但我不允许对其他答案发表评论。如果删除'not-null'属性（如下所示），它是否按预期工作？

 < property name =isActivetype =java我相信这就是导致异常的原因。 .lang.Short> 
< meta attribute =default-value> 1< / meta> 
< column name =IsActive/> 
< / property> 
  

org.hibernate.PropertyValueException: not-null property references a 
null or transient value

I am using Java,Hibernate and MySQL 5.1.52-log version.

My interpretation of default is if I don't supply value for the column, Hibernate will insert the default value when I try to save this object.

HBM file,

<property name="isActive" type="java.lang.Short">
        <column name="IsActive" not-null="true" default="1"/>
</property>

解决方案

According to the documentation of PropertyValueException, if you set a null value in a property declared not-null="true" and then try to persist/update it, then you will get this exception.

See http://docs.jboss.org/hibernate/orm/3.5/javadoc/org/hibernate/PropertyValueException.html

You should remove the not-null="true" attribute from the config (because the default value of not-null is false) and then the database should insert the default value that you specified in the configuration for you (in this case '1').

[UPDATE]

I would have preferred to put this as a comment in fujy's answer but I am not allowed to comment on other answers yet. Does it work as expected if you remove the 'not-null' attribute (As I am showing below)? I believe that is what is causing the exception that you are getting.

 <property name="isActive" type="java.lang.Short">
     <meta attribute="default-value">1</meta>
     <column name="IsActive" />
 </property>

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