NHibernate - filtering out results based on child-property

问题

I have this code fetching all enabled Groups with their children. The problem I have is that the children can also be disabled but I can't get fluent nhibernate to only fetch groups where all childrens are enabled. I assume this is possible but how?

public class Group {
    public bool IsDisabled { get; set; }
    public string Description { get; set; }
    public ICollection<ChildType> Children { get; protected set; }
}

public class ChildType {
    public bool IsDisabled { get; set; }
    public string Description { get; set; }
}

public IList<Group> Search(string searchString) {
    IQueryOver<Group> query = Session.QueryOver<Group>()
        .WhereRestrictionOn(x => x.Description).IsInsensitiveLike(searchString, MatchMode.Start)
        .Where(x => !x.IsDisabled)
        .OrderBy(x => x.Description).Asc
        .Fetch(group => group.Children).Eager;

    return query
        .Cacheable()
        .List();
}

Edit: There is a N:M-relation between children and groups.

The following is the solution I used:

public class Group {
    public long Id { get; set; }
    public bool IsDisabled { get; set; }
    public string Description { get; set; }
    public ICollection<ChildType> Children { get; protected set; }
}

public class ChildType {
    public long Id { get; set; }
    public bool IsDisabled { get; set; }
    public string Description { get; set; }
    public ICollection<Group> Groups { get; protected set; }
}

public IList<Group> Search(string searchString) {
    ChildType child = null;
    Group group = null;
    Group joinedGroup = null;

    var notDisabled = Session.QueryOver.Of<ExaminationType>()
        .Where(x => x.IsDisabled)
        .JoinAlias(x => x.Groups, () => joinedGroup )
            .Where(x => joinedGroup == group)
        .Select(x => x.Id);

    IQueryOver<Group> query = Session.QueryOver<Group>()
        .WhereRestrictionOn(x => x.Description).IsInsensitiveLike(searchString, MatchMode.Start)
        .JoinAlias(x => x.ExaminationTypes, () => child)
        .WithSubquery.WhereNotExists(notDisabled)
        .OrderBy(x => x.Description).Asc;

    return query
        .Cacheable()
        .List();
}

回答1:

You need to use a subquery in order to achieve what you want. In order to do this though you're going to need to add a Group reference to the ChildType entity.

Group group = null;
var childCrit = QueryOver.Of<ChildType>()
        .Where(c => c.Group == group).And(c => c.IsDisabled)
        .Select(c => c.Id);
var query = Session.QueryOver(() => group)
        .WhereRestrictionOn(x => x.Description).IsInsensitiveLike(searchString, MatchMode.Start)
        .Where(x => !x.IsDisabled)
        .WithSubquery.WhereNotExists(childCrit)
        .OrderBy(x => x.Description).Asc
        .Fetch(group => group.Children).Eager;

This will get all groups that aren't disabled and have no disabled children.

回答2:

public IList<Group> Search(string searchString) {

    Children children = null;

    IQueryOver<Group> query = Session.QueryOver<Group>()
        .WhereRestrictionOn(x => x.Description).IsInsensitiveLike(searchString, MatchMode.Start)
        .Where(x => !x.IsDisabled)
        .JoinAlias(x => x.Children, () => children)
            .Where(x => !x.IsDisabled)
        .OrderBy(x => x.Description).Asc;

    return query
        .Cacheable()
        .List();
}

That should do what you want to do.

Joining an alias will also fetch it for you.

http://www.philliphaydon.com/2011/04/nhibernate-querying-relationships-are-depth/

来源：https://stackoverflow.com/questions/5790153/nhibernate-filtering-out-results-based-on-child-property

标签

nhibernate

fluent-nhibernate

queryover