I compiled the fluent nhibernate 1.0 rc with nhibernate 2.1 and had several warnings after the errors were fixed.
Fluent nhibernate tells me to use a separate Subclass-map instead of JoinedSubclass.
Current Mapping:
public class ClientMap : ClassMap<Client>
{
public ClientMap()
{
LazyLoad();
Id(x => x.Id);
//some boring stuff in between
JoinedSubClass<Company>("Id", m =>
{
m.LazyLoad();
m.Map(x => x.Name);
m.Map(x => x.Form);
});
}
The classes are inherited (company : client).
I tried the new mapping as follows:
public class CompanyMap : SubclassMap<Company>
{
CompanyMap()
{
LazyLoad();
Map(x => x.Name);
Map(x => x.Form);
}
}
After this change I don't get any companies, I'm not sure about how hibernate correctly knows what to do. Before I sayd "look, I have this class and the subclass I give you straight away in your mapping" and now: "Here are two mappings, figure by yourself, thx" :)
Any advices how to get the new subclass-mapping corrected?
Update:
Now I figured out that this works for saving data but the fk ID is not written to the child. How do I map the FK? The field name is Client_id, as nhibernate expects fk field names..
Related
I have Survey that HasMany Question that HasMany Option.
I want to create a reference from Option to Survey.
The problem is that Every time I want to create a new Survey with all of its children, I need to loop on all survey.Questions and loop on all survey.Questions.Options and set o each Option the Survey (or else Nhibernate will create a new Survey for each Option)
** I dont want to have IList<Option> on Survey if I do that it will solve the problem but it would be heavy and unusable **
public class SurveyMap : ClassMap<Survey>
{
public SurveyMap()
{
Id(x => x.Id).GeneratedBy.Identity();
HasMany(x => x.Questions).KeyColumn("SurveyId").Inverse().AsBag().Not.LazyLoad().Cascade.SaveUpdate();
}
}
public class QuestionMap : ClassMap<Question>
{
public QuestionMap()
{
Id(x => x.Id).GeneratedBy.Identity();
HasMany(x => x.Options).KeyColumn("QuestionId").Inverse().AsBag().Cascade.SaveUpdate();
}
}
public class OptionMap : ClassMap<Option>
{
public OptionMap()
{
Id(x => x.Id).GeneratedBy.Identity();
References(x => x.Survey).Column("SurveyId").Cascade.All();
}
}
It might be better to separate your reporting concerns from your applications business logic concerns. Use the mappings that you already have for your applications business logic, and provide a different interface into the data for your reporting requirements. You could use either HQL, SQL or new objects and maps for this.
I'm just getting up to speed with NHibernate 3.2 and its "mapping by code" feature, and migrating our Fluent mapping over to it.
Is there an equivalent of the fluent "ReadOnly();" function, to make the entire mapping read only?
Thanks in advance.
Use Mutable(false) in the mapping.
Read this post for corresponding hbm file mapping from where I could infer this.
http://davybrion.com/blog/2007/08/read-only-data-in-nhibernate/
Use PropertyMapper action to define access style:
public class EntityMapping : ClassMapping<Entity>
{
public EntityMapping()
{
Id(m => m.Id, map => map.Generator(Generators.HighLow));
Property(m => m.Name, map => map.Access(Accessor.ReadOnly));
}
}
For those looking for this in fluent you are looking for ReadOnly() as below:
public class FooMap : ClassMap<Foo> {
public FooMap() {
Schema("bar");
Table("foo");
LazyLoad();
ReadOnly();
CompositeId()
.KeyProperty(x => x.ID, "ID")
.KeyProperty(x => x.Year, "Year");
Map(x => x.FirstField).Column("FirstField").Length(1);
}
}
Our entities have a group of common properties. In order to reduce repetitive mapping, I created a base ClassMap that maps the identities and common properties. For each entity's ClassMap I just subclass the base and it works great. For a new project we are also letting NH generate the DB schema for us. The issue is, the order of the columns is such that the properties from the base ClassMap appear first, followed by anything mapped in the sub class. The requirement for this build is that the columns appear in a specific order.
To get around this I did the following.
public class BaseMap<T> : ClassMap<T> where T : Entity
{
public BaseMap()
{
Id(x => x.Id);
MapEntity();
Map(x => x.CommonProperty1);
Map(x => x.CommonProperty2);
Map(x => x.CommonProperty3);
}
protected virtual void MapEntity()
{
}
}
public class SomeEntityMap : BaseMap<SomeEntity>
{
public SomeEntity()
{
base.MapEntity();
}
protected override void MapEntity()
{
Map(x => x.SomeEntityProperty1);
Map(x => x.SomeEntityProperty2);
Map(x => x.SomeEntityProperty3);
}
}
This works, but feels like a hack. Aside from the hack factor, is there anything here that could be problematic?
If you made the base class and map method abstract it would feel less hacky...
public abstract class BaseMap<T> : ClassMap<T> where T : Entity
{
public BaseMap()
{
Id(x => x.Id);
MapEntity();
Map(x => x.CommonProperty1);
Map(x => x.CommonProperty2);
Map(x => x.CommonProperty3);
}
protected abstract void MapEntity();
}
public class SomeEntityMap : BaseMap<SomeEntity>
{
protected override void MapEntity()
{
Map(x => x.SomeEntityProperty1);
Map(x => x.SomeEntityProperty2);
Map(x => x.SomeEntityProperty3);
}
}
This would keep the common property columns at the end of the table. Be aware that foreign key columns will still get added after those. I don't think there is any way to have full control of the column order w/ fluent, unless you hand-modify the create schema scripts.
I just had to implement something similar myself.
Assuming that you have
public class SomeEntity : Entity
{
...
}
A less 'hack-like' way would be:
public abstract class BaseMap<T> : ClassMap<T> where T : Entity
{
public BaseMap()
{
Id(x => x.Id);
Map(x => x.CommonProperty1);
Map(x => x.CommonProperty2);
Map(x => x.CommonProperty3);
}
}
public class SomeEntityMap : BaseMap<SomeEntity>
{
public SomeEntity()
{
Map(x => x.SomeEntityProperty1);
Map(x => x.SomeEntityProperty2);
Map(x => x.SomeEntityProperty3);
}
}
Same result in the end, but your not using overridden methods to add mappings. It'll be taken care of automagically.
having a little trouble with a mapping for the following table setup currently:
Shop
[1] [1]
/ \
[n] [n]
Category-[m]---[n]-Article
The behaviour should be the following :
1 - when deleting a shop, all Articles and Categories Should be deleted
2 - when deleting a Category, related Articles should be unassigned but not deleted
3 - when deleting an Article, related Categories should be unassigned but not deleted
Here's the current mapping:
public class ShopMap: ClassMap<Shop>
{
public ShopMap()
{
this.Table("shop");
Id(x => x.Id).Column("id").GeneratedBy.Native();
Map(x => x.Name).Column("name");
HasMany(x => x.Categories).Cascade.AllDeleteOrphan;
HasMany(x => x.Articles).Cascade.AllDeleteOrphan;
}
}
public class CategoryMap: ClassMap<Category>
{
public CategoryMap()
{
this.Table("category");
Id(x => x.Id).Column("id").GeneratedBy.Native();
Map(x => x.Name).Column("name");
References(x => x.Shop);
HasManyToMany(x => x.Articles).Cascade.AllDeleteOrphan()
.Table("article_category")
.ChildKeyColumn("article_id")
.ParentKeyColumn("category_id")
.Inverse();
}
}
public class ArticleMap: ClassMap<Article>
{
public ArticleMap()
{
this.Table("article");
Id(x => x.Id).Column("id").GeneratedBy.Native();
Map(x => x.Name).Column("name");
References(x => x.Shop);
HasManyToMany(x => x.Categories).Cascade.All()
.Table("article_category")
.ParentKeyColumn("article_id")
.ChildKeyColumn("category_id");
}
}
When deleting a Category (Session.Delete()), NH tries to delete the related Articles as well. Changing the Cascade-Mode to SaveUpdate will fix this, but will leave the entries in the link table *article_category*. Summing up : Cascade.SaveUpdate is too lazy, Cascade.All is too eager.
I tried everything that came to my mind in the mappings, but couldn't find a correct way to map this (rather simple schema).
Any ideas on how to (fluently) map this are greatly appreciated!
Thanks in advance
Sebi
The entries are left in the link table because Category.Articles is defined as the inverse side of the relationship. You need to remove the Category from Article.Categories before deleting it in order for the link record to be removed.
I have a set of fluent object mappings that looks like this:
public class UserMap : ClassMap<User>
{
public UserMap()
{
Map(x => x.Id);
Map(x => x.Status);
}
}
public class SpecialUserMap : SubClassMap<SpecialUser>
{
public SpecialUserMap()
{
Map(x => x.Property);
}
}
public class DirectoryMap : ClassMap<Directory>
{
public DirectoryMap
{
Map(x => x.Id);
HasMany(x => x.SpecialUsers).Where("Status = 0");
}
}
User is a join table, which SpecialUser joins against to get things like status. However, when I try to reference a SpecialUser in Directory's SpecialUsers collection, I get an error of "Undefined column 'Status'", as in the generated SQL, NHibernate tries to grab the Status column from the SpecialUser table, and not the User table.
Is there a way to explicitly tell NHibernate which table to get the Status column in the DirectoryMapping?
The Status property of a User / SpecialUser needs to map onto a single column in the database. You can't have it coming sometimes from User and sometimes from SpecialUser.
As a workaround, you could add a SpecialUserStatus property to SpecialUser, and then you could query on that easily.
That mappings looks right for table-per-subclass mapping, assuming that SpecialUser extends User. My guess is that it's a bug.