Yet another newbies question abount cascading

mosspower · **Joined:** Wed Jul 18, 2007 3:54 pm **Posts:** 2

Hello,

I have a question about cascading. It is about a one to many relationship between Word and WordExpression. In the mapping file the cascade for the bag is set to save-update.

This code works just fine:

Code:

 
Word word = new Word();
word.Catalogue = "My new word";
word.Subject = new Subject(3);

WordExpression wordExpression = new WordExpression();
wordExpression.Catalogue = "Some expression #1 for new word";
wordExpression.Word = word;

word.WordExpressions.Add(wordExpression);

NHDataManager.Save(word, exchangeContext);

How can I avoid the assignment?

wordExpression.Word = word;

I thought NHibernate knows that fact because of the mapping file. Do I really have to assign for each new WordExpression the word manually or did I just missed some points here?

Thx 4 any help.

marcal · **Posted:** Wed Jul 25, 2007 9:57 pm

mosspower wrote:

How can I avoid the assignment?

You can't. However, you can clean things up in your domain objects by adding a method like this:

Code:

public void AddExpression(WordExpression w) {
   WordExpressions.Add( w );
   w.Word = this;
}

See here, especially the paragraph starting "To tighten things up a bit,..."

xasp · **Posted:** Thu Jul 26, 2007 2:51 am

If your WordExpressions-collection is mapped with the inverse attribute, you must use the assignment.

If it is not mapped inverse, then it will be updated without using that assignment, but 2 sql statements will be issued and you have the risk that you're violating not null constraints on your database (see the link marcal refers to).