java - Hibernate + MSSQL，无法将值 NULL 插入列中

Question

拥有 Hibernate 和 MSSQL 环境。我遇到过错误:'无法将 NULL 值插入表'CHT.dbo.reporter_comments'的'comment_id'列；列不允许为空。插入失败。 hibernate 配置:

<id unsaved-value = "null" type = "int" name="commentId" column="comment_id">
  <generator class="identity"/>
</id>

    <property name="reporterId" column="REPORTERID" />
    <property name="adminComments" column="COMMENT" />
    <property name="commentDate" column="COMMENT_DATE"/>
    <property name="commentBy" column="COMMENT_BY"/>

“comment_id”列在数据库中具有“identity”属性:如果我使用数据库客户端进行插入:

insert into REPORTER_COMMENTS (REPORTERID, COMMENT, COMMENT_DATE, COMMENT_BY) 
values (15119, 'test', '2013-03-04 05:45:25', 'admin');

它非常适合我。

hibernate 日志:

DEBUG hibernate.SQL - insert into REPORTER_COMMENTS (REPORTERID, COMMENT, COMMENT_DATE, COMMENT_BY) values (?, ?, ?, ?) DEBUG hibernate.jdbc.AbstractBatcher - preparing statement DEBUG hibernate.persister.entity.AbstractEntityPersister - Dehydrating entity: [---.ReporterComments#] DEBUG hibernate.type.LongType - binding '15119' to parameter: 1 DEBUG hibernate.type.StringType - binding 'test' to parameter: 2 DEBUG hibernate.type.TimestampType - binding '2013-03-04 06:13:02' to parameter: 3 DEBUG hibernate.type.StringType - binding 'dw' to parameter: 4 DEBUG hibernate.jdbc.AbstractBatcher - about to close PreparedStatement (open PreparedStatements: 1, globally: 1) DEBUG hibernate.jdbc.AbstractBatcher - closing statement DEBUG hibernate.util.JDBCExceptionReporter - could not insert: [---.ReporterComments] [insert into REPORTER_COMMENTS (REPORTERID, COMMENT, COMMENT_DATE, COMMENT_BY) values (?, ?, ?, ?)] java.sql.SQLException: [BEA][SQLServer JDBC Driver][SQLServer]Cannot insert the value NULL into column 'comment_id', table 'CHT.dbo.reporter_comments'; column does not allow nulls. INSERT fails.

谢谢!

Answer 1

您的 comment_id 列实际上是 IDENTITY 列吗？如果不是，那么这就是您的问题，因为在使用身份生成器时，Hibernate 不会在插入语句中包含 comment_id 列，而是依赖数据库来生成值。