GORM/Grails - add extra column to a joinTable expression

问题

I have a Domain Class setup similar to this

class NewsStory {
  String headline
  static hasMany = [channels:Channel]
  static mapping = {
      table 'NewsStory'
      addresses joinTable:[name:'Article_Channel', key:'ArticleId', column:'ChannelId']
  }
}

in the Article_Channel table i need to have an extra column populated called ArticleType say. Its value will always be the same e.g. 'news' for this domain class, but will be differnt for others e.g. 'blog' Channel is just something like 'Security' etc

Is there a way? Thanks

回答1:

One option would be be to create your own many-to-many mapping class and add the field in there.

http://grails.org/Many-to-Many+Mapping+without+Hibernate+XML

So, for example:

class ArticleChannel {
    NewsStory newsStory
    Channel channel
    String articleType
}

Then, your NewsStory and Channel classes would hasMany the ArticleChannel class.

来源：https://stackoverflow.com/questions/7867621/gorm-grails-add-extra-column-to-a-jointable-expression