I have the following situation with fluent nhibernate:
public class Stuff
{
public Stuff()
{
Entities = new List<Entity>();
}
public virtual int Id { get; set; }
public virtual IList<Entity> Entities { get; set; }
}
public abstract class Entity
{
public virtual int Id { get; set; }
public virtual string Type { get; set; }
public virtual Stuff Stuff { get; set; }
}
public class Person : Entity
{
public virtual string FirstName { get; set; }
public virtual string LastName { get; set; }
}
public class Animal : Entity
{
public virtual string Species { get; set; }
}
And then, i have the following code to use automap and generate these mappings:
var sessionFactory =
Fluently.Configure().Database(persistenceConfigurer).Mappings(
m =>
m.AutoMappings.Add(
AutoMap.Source(new Types(typeof(Entity), typeof(Person), typeof(Animal), typeof(Stuff))))
.ExportTo(#"e:\")).ExposeConfiguration(BuildSchema).BuildSessionFactory();
however, what's happening is that i get the following exception:
---> NHibernate.MappingException: Association references unmapped class: ConsoleApplication1.Models.Entity
if i make the entity class non abstract this works, however, i'd like to avoid having that table in the database but still maintain the hierarchy concept with the re
You need to add your auto mappings like this
AutoMap.AssemblyOf<Entity>(yourConfiguration).IgnoreBase<Entity>();
Not only will this ignore your Entity base class but you don't need to add each entity manually so long as each model inherits from Entity.
Related
As entity framework states, "Code first", here we go with the code first...
public class BaseModel
{
[Key]
public Guid Id { get; set; }
public DateTime DateCreated { get; set; }
public DateTime DateChanged { get; set; }
public BaseModel()
{
this.Id = Guid.NewGuid();
this.DateCreated = DateTime.Now;
this.DateChanged = DateTime.Now;
}
}
public class Association: BaseModel
{
public string Name { get; set; }
public string Type { get; set; }
public virtual List<Rule> Rules { get; set; }
public Association()
: base()
{
}
}
public class Rule: BaseModel
{
[ForeignKey("Association")]
public Guid AssociationId { get; set; }
//[Required]
public virtual Association Association { get; set; }
//[Required]
public string Name { get; set; }
public string Expression { get; set; }
public virtual List<Action> Actions { get; set; }
public Rule()
: base()
{
}
}
public class Action: BaseModel
{
public string Name { get; set; }
public string ActionType { get; set; }
[ForeignKey("Rule")]
public Guid RuleId { get; set; }
public virtual Rule Rule { get; set; }
public int Order { get; set; }
public Action()
: base()
{
}
}
So these are my four model classes that are using entity framework code first.
Each inherit from the baseclass, so they all have an Id Guid as Primary Key.
An Association has a list of rules. (Rule has FK to Association)
A Rule as has a list of actions. (Action has FK to Rule)
What I would like to do is only change and save the most upwards class = Association.
For example when deleting a rule, I would like this code to work:
public ActionResult DeleteRule(Guid assId, Guid ruleId)
{
Association ass = this.DataContext.Associations.FirstOrDefault(a => a.Id == assId);
ass.Rules.RemoveAll(r => r.Id == ruleId);
this.DataContext.SaveChanges();
return RedirectToAction("Index");
}
On the context.savechanges this is giving me this error:
'The operation failed: The relationship could not be changed because one or more of the foreign-key properties is non-nullable. When a change is made to a relationship, the related foreign-key property is set to a null value. If the foreign-key does not support null values, a new relationship must be defined, the foreign-key property must be assigned another non-null value, or the unrelated object must be deleted.'
This error also occurs when deleting an action.
Is there a way to change the most upper (Association) object AND ONLY changing things to this Association.
I DO NOT want to say context.Rules.remove(...) or context.actions.remove(...)
here's the source: http://server.thomasgielissen.be/files/mvctesting.zip
you need VS2012, all nuget packages are included in zip and you should be able to build and run the project.
Thanks in advance for your feedback!
Greetz,
Thomas
I you want to fix this issue, you should store your relations through junction tables. I don't think that you can achieve what you need, with this model.
However if you put a junction table(or entity) between your entities, you can easily remove child objects and update parent object.
For example, put a junction entity between Association and Rule:
public class AssociationRule: BaseModel
{
public Guid AssociationId { get; set; }
public Guid RuleId { get; set; }
[ForeignKey("AssociationId")]
public virtual Association Association { get; set; }
[ForeignKey("RuleId")]
public virtual Rule Rule { get; set; }
public Association()
: base()
{
}
}
Now, you can easily remove any rule from any association:
public ActionResult DeleteRule(Guid assId, Guid ruleId)
{
AssociationRule assr = this.DataContext
.AssociationRuless
.FirstOrDefault(ar => ar.AssociationId == assId && ar.RuleId == ruleId);
this.DataContext.AssociationRules.Remove(assr);
this.DataContext.SaveChanges();
return RedirectToAction("Index");
}
I have a problem with NHibernate for a longtime which I solved by non-optimal ways/workarounds.
First of all, I'm using WCF REST to communicate with my client application. As you know, serializing persisted entities is not a best practise and always causes other problems. Thus, I always map my entities to DTO's with NHibernates Transformers. The problem is that I have entities which are more complex to use Transformers to convert them.
How can I map sub entities to sub dto's by using transformers or any other nhibernate feature?
Note: I don't want to use 3rd parties like Automapper.
These are the Entities and DTO's which I want to map. Variable names are exactly same with each other.
Entity Classes:
EntityType
public class crmEntityType : EntityModel<crmEntityType>
{
public crmEntityType()
{
Association = new List<crmEntityType>();
Fields = new List<crmCustomField>();
}
public virtual int ID { get; set; }
public virtual string Title { get; set; }
public virtual ICollection<crmEntityType> Associations { get; set; }
public virtual ICollection<crmCustomField> Fields { get; set; }
}
CustomFields
public class crmCustomField : EntityModel<crmCustomField>
{
public virtual int ID { get; set; }
public virtual string Name { get; set; }
public virtual crmEntityType EntityType { get; set; }
}
DTO's
EntityTypeDTO
[DataContract]
public class EntityTypeDTO
{
[DataMember]
public int ID { get; set; }
[DataMember]
public string Title { get; set; }
[DataMember]
public IList<CustomFieldDTO> Fields { get; set; }
[DataMember]
public int[] Associations { get; set; }
}
CustomFieldDTO
[DataContract]
public class CustomFieldDTO
{
[DataMember]
public int ID { get; set; }
[DataMember]
public string Name { get; set; }
[DataMember]
public int EntityType { get; set; }
[DataMember]
public int FieldType { get; set; }
}
I found my solution by spending my day and night to work it out. Finally, I've got the best solution I could find. I hope it helps someone in my condition some day.
This linq query works with just one database round-trip. I think it maps the classes in memory.
return (from entityType in Provider.GetSession().Query<crmEntityType>()
.Fetch(x => x.Association)
.Fetch(x => x.Fields)
.AsEnumerable()
select new EntityTypeDTO()
{
ID = entityType.ID,
Title = entityType.Title,
Association = entityType.Association.Distinct()
.Select(asc => asc.ID).ToArray<int>(),
Fields = entityType.Fields.Distinct()
.Select(fi => new CustomFieldDTO
{ ID = fi.ID,
Name = fi.Name,
Value = fi.Value,
EntityType = fi.EntityType.ID,
Type = fi.Type
}).ToList()
}).ToList();
I'm using nhibernate envers to audit my data / save previous versions.
What I'd like to do is store previous versions against the parent entity.
Something like this:
public abstract class BookBase
{
public virtual int ID { get; set; }
public virtual string Name { get; set; }
public virtual string Author { get; set; }
}
public class Book : BookBase
{
public virtual ICollection<BookRevision> PreviousVersions { get; set; }
}
public class BookRevision : BookBase
{
public virtual int VersionNumber { get; set; }
public virtual DateTime VersionTimeStamp { get; set; }
}
Is that possible with envers nhibernate (using fluent nHibernate for mappings)
What would my envers config need to look like?
What would my mappings need to look like?
Envers handles auditing for you, you don't have to define your own auditing types in your domain model.
Define (and map it as normal) your entity
public class Book
{
public virtual int ID { get; set; }
public virtual string Name { get; set; }
public virtual string Author { get; set; }
}
If you want to do auditing on Book modifications, configure Envers like this
var enversCfg = new FluentConfiguration();
enversCfg.Audit<Book>();
yourNhCoreConfiguration.IntegrateWithEnvers(enversCfg);
I have the following database tables defined:
Club: Id, Name
Member: Id, Name
ClubMember: ClubId, MemberId
I have the following entity Classes defined:
public class Club() {
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual IList<Member> Members { get; set; }
}
public class Member() {
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual IList<Club> Clubs { get; set; }
}
I have the following overrides defined:
public class MemberOverride : IAutoMappingOverride<Member>
{
public void Override(AutoMapping<Member> mapping_)
{
mapping_
.HasManyToMany(x_ => x_.Clubs)
.ParentKeyColumn("MemberId")
.ChildKeyColumn("ClubId")
.Cascade.All()
.Table("ClubMembers");
}
}
public class ClubOverride : IAutoMappingOverride<Club>
{
public void Override(AutoMapping<Club> mapping_)
{
mapping_
.HasManyToMany(x_ => x_.Members)
.ParentKeyColumn("ClubId")
.ChildKeyColumn("MemberId")
.Inverse()
.Table("ClubMembers");
}
}
I can see from my overrides that the Inverse on the ClubOverride means you cannot do the following
session.Save(club.Members.Add(member));
but this works:
session.Save(member.Clubs.Add(club);
But it doesn't make logical sense. I want to be able to save either the club with members or member with clubs.
Am I trying to do something impossible with FluentNhibernate?
TIA
Yes, you're right, that's not possible. But it's not a question of FluentNhibernate, NHibernate works like that.
Only one side is the owner of the relation and on charge of adding elements.
From official documentation:
Changes made only to the inverse end of the association are not persisted. This means that NHibernate has two representations in memory for every bidirectional association, one link from A to B and another link from B to A. This is easier to understand if you think about the .NET object model and how we create a many-to-many relationship in C#:
You can create add or remove methods on your entities that will help accomplish this:
public class Club() {
public virtual int Id { get; set; }
public virtual string Name { get; set; }
private IList<Member> members;
public virtual IEnumerable<Member> Members { get { return members.Select(x => x); } }
public Club() {
members = new List<Member>();
}
public virtual void AddMember(Member member){
if (members.Contains(member))
return;
members.Add(user);
member.AddClub(this);
}
public virtual void RemoveMember(Member member){
if (!members.Contains(member))
return;
members.Remove(member);
member.RemoveClub(this);
}
}
My class:
[PersistClass]
public class ExternalAccount
{
public virtual AccountType AccountType { get; set; }
public virtual int Id { get; private set; }
public virtual User User { get; set; }
public virtual Dictionary<string, string> Parameters { get; set; }
public ExternalAccount()
{
Parameters = new Dictionary<string, string>();
}
}
The Dictionary is not getting mapped. I understand that automapping doesn't work by default with Dictionaries, how do I configure the mapping? All Parameters is is a list of key/value pairs - so I would expect them to be stored in a table with a foreign key to the externalaccount table. I know I can do this with another class - but it makes access to the parameters in the class more difficult - I'd rather have to configure the complexity once.
Please bear in mind I am new Fluent and to nHibernate.
Thanks
Using a simple class relationship such as the following:
public class Foo {
public virtual IDictionary<string, Bar> Bars { get; set; }
}
public class Bar {
public virtual string Type { get; set; }
public virtual int Value { get; set; }
}
You can map this with Fluent NHibernate in this way:
mapping.HasMany(x => x.Bars)
.AsMap(x => x.Type);
Where Bar.Type is used as the index field into the dictionary.
FluentNHibernate mapping for Dictionary