NHibernate Query across multiple tables

问题:

I am using NHibernate, and am trying to figure out how to write a query, that searchs all the names of my entities, and lists the results. As a simple example, I have the following objects;

public class Cat {
public string name {get; set;}
}

public class Dog {
    public string name {get; set;}
}

public class Owner {
    public string firstname {get; set;}
    public string lastname {get; set;}
}

Eventaully I want to create a query , say for example, which and returns all the pet owners with an name containing "ted", OR pets with a name containing "ted".

Here is an example of the SQL I want to execute:

SELECT TOP 10 d.*, c.*, o.* FROM owners AS o
INNER JOIN dogs AS d ON o.id = d.ownerId 
INNER JOIN cats AS c ON o.id = c.ownerId
WHERE o.lastname like '%ted%' 
OR o.firstname like '%ted%' 
OR c.name like '%ted%' 
OR d.name like '%ted%' 

When I do it using Criteria like this:

    var criteria = session.CreateCriteria<Owner>()
        .Add(
        Restrictions.Disjunction()
            .Add(Restrictions.Like("FirstName", keyword, MatchMode.Anywhere))
            .Add(Restrictions.Like("LastName", keyword, MatchMode.Anywhere))
        )
        .CreateCriteria("Dog").Add(Restrictions.Like("Name", keyword, MatchMode.Anywhere))
        .CreateCriteria("Cat").Add(Restrictions.Like("Name", keyword, MatchMode.Anywhere));
        return criteria.List<Owner>();

The following query is generated:

   SELECT TOP 10 d.*, c.*, o.* FROM owners AS o
   INNER JOIN dogs AS d ON o.id = d.ownerId 
   INNER JOIN cats AS c ON o.id = c.ownerId 
   WHERE o.lastname like '%ted%' 
   OR o.firstname like '%ted%' 
   AND d.name like '%ted%'
   AND c.name like '%ted%'

How can I adjust my query so that the .CreateCriteria("Dog") and .CreateCriteria("Cat") generate an OR instead of the AND?

thanks for your help.

回答1:

Try this, it might work.

var criteria = session.CreateCriteria<Owner>()
            .CreateAlias("Dog", "d")
            .CreateAlias("Cat", "c")
            .Add(
            Restrictions.Disjunction()
                .Add(Restrictions.Like("FirstName", keyword, MatchMode.Anywhere))
                .Add(Restrictions.Like("LastName", keyword, MatchMode.Anywhere))
                .Add(Restrictions.Like("c.Name", keyword, MatchMode.Anywhere))
                .Add(Restrictions.Like("d.Name", keyword, MatchMode.Anywhere))
            );

回答2:

You need to combine the two criteria using Expression.Or(criteria1, criteria2)

More here: http://devlicio.us/blogs/derik_whittaker/archive/2009/04/21/creating-a-nested-or-statement-with-nhibernate-using-the-criteria-convention.aspx

Hmm I think it would look like this (borrowed a bit from BuggyDigger's code)

var criteria = session.CreateCriteria<Owner>()
    .CreateAlias("Dog", "d")
    .CreateAlias("Cat", "c")
    .Add(Expression.Or(Expression.Like("c.Name", keyword, MatchMode.Anywhere)
            , Expression.Like("d.Name", keyword, MatchMode.Anywhere))
        );

But I didn't notice that you wanted to OR everything. In that case adding these criteria to the disjunction, as BuggyDigger showed, is probably the way to go.