I have a similar mapping - Post and Tag - where one Post can have several
tags, which are just strings (sorry, don't have time to change it):
this.Set(x => x.Tags, x =>
{
x.Key(y =>
{
y.Column("post_id");
y.NotNullable(true);
});
x.Cascade(Cascade.All);
x.Lazy(CollectionLazy.NoLazy);
x.Fetch(CollectionFetchMode.Join);
x.Table("tag");
}, x =>
{
x.Element(y =>
{
y.Column("tag");
y.Length(20);
y.NotNullable(true);
y.Unique(true);
});
});
I am using set instead of bag, this is generally better, and in your case,
I imagine you don't want duplicate values stored.
See if this works!
RP
On Thursday, May 15, 2014 11:31:13 AM UTC+1, Dawid Ciecierski wrote:
>
> Hello,
>
> Let me start by asking the moderator to please look at my previous post
> sent around Friday (May 9), as it went into much greater detail as well as
> linked to a sample project but for some reason was not approved... Would be
> grateful if you could look at it again as I spend a good several minutes
> describing what I'm trying to accomplish as best I could.
>
> Also wanted to add that this is a sister post to one on the developers
> group<https://groups.google.com/forum/#!topic/nhibernate-development/UTbygrpFz04>,
>
> in which I tried to go into more technical aspects of this issue, but was
> still directed to this group :-)
>
> Without further ado thou. What I have is frequently updated and delete-d
> entity that is just a view on a more complex business domain. Each entity
> in this "view" has a child collection of simple strings (think tags).
> Because of the DELETE FROM [TableName] we regularly execute, I'd like to
> mark the foreign key relationship as ON DELETE CASCADE. Right now I do so
> manually but only because I've found no way to coerce NHibernate into
> seeing the relationship the same way. Ultimately I'd like to find a way to
> do so as the whole database is frequently rebuilt from scratch by
> SchemaExport and doing manual updates to multiple foreign key relationships
> is time-consuming. Below is a simple class with its mapping demonstrating
> the use case:
>
> public class Photo
> {
> public int Id { get; set; }
> public string Name { get; set; }
> public IList<string> Tags { get; set; }
>
> public Photo()
> {
> Tags = new List<string>();
> }
> }
>
> public class PhotoMap : ClassMapping<Photo>
> {
> public PhotoMap()
> {
> Lazy(false);
> Id(p => p.Id);
> Property(p => p.Name);
> Bag(
> p => p.Tags,
> collectionMapping: collectionMapping =>
> {
> //collectionMapping.Inverse(true);
> collectionMapping.Lazy(CollectionLazy.NoLazy);
> collectionMapping.Cascade(Cascade.All | Cascade.DeleteOrphans);
> },
> mapping: mapping =>
> {
> //mapping.OneToMany(); // NH does not like this
> mapping.Element(e => e.Column("tag_value"));
> });
> }
> }
>
> When I uncomment the mapping.OneToMany line NHibernate tells me that
> there is an unmapped entity System.String, so clearly I'm going against its
> way of thinking (and on the developers' group Ricardo confirmed that
> one-to-many is for entities only). Will be grateful for any advice on how I
> can make it work.
>
> Best regards,
> Dawid Ciecierski
>
> Ps. I've prepared a sample project that does not make actual database
> calls which I can link to, but will refrain myself from doing so just in
> case linking outside of Google Groups automatically puts my post in the
> moderator's trash.
>
--
You received this message because you are subscribed to the Google Groups
"nhusers" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/nhusers.
For more options, visit https://groups.google.com/d/optout.
