I'm trying to get the AutoPersistence model to map several composite elements. However, it seems that either I end up mapping it as an entity, dropping down to manual mapping or it just doesn't plain work. Here's some code that demonstrates my problem:
using System;
using System.Collections.Generic;
using FluentNHibernate.AutoMap;
using FluentNHibernate.Cfg;
using FluentNHibernate.Conventions.Helpers;
using NHibernate.Cfg;
namespace Scanner {
public class Root {
public int Id { get; set; }
public string Name { get; set; }
public ICollection<Component> Components { get; set; }
}
public class Component {
public string Name { get; set; }
}
class Example {
public void DoesntGetComponents()
{
Configuration configuration = new Configuration();
configuration.SetProperty("ConnectionString", "");
configuration.SetProperty("dialect", "NHibernate.Dialect.MsSql2005Dialect");
var config = Fluently.Configure(configuration)
.Mappings(m => m.AutoMappings.Add(AutoMapping))
.BuildConfiguration();
var sql2005 = new NHibernate.Dialect.MsSql2005Dialect();
foreach (var line in config.GenerateSchemaCreationScript(sql2005))
{
Console.WriteLine(line);
}
}
static AutoPersistenceModel AutoMapping() {
AutoPersistenceModel model = new AutoPersistenceModel();
return model
.AddEntityAssembly(typeof(Root).Assembly)
.WithSetup(e => e.IsComponentType = t => t == typeof(Component))
.Where(t => t == typeof(Root))
.MergeWithAutoMapsFromAssemblyOf<Root>()
.ConventionDiscovery.Add(ForeignKey.Format((p, t) => (p == null ? t.Name : p.Name) + "Id"))
.ConventionDiscovery.Add(Table.Is(t => t.EntityType.Name))
;
}
}
}
(Sorry it's so long, but it's the minimal code required to demonstrate the problem. This particular version of the code fails to register the component type at all.
So, what am I doing wrong?
It seems that the component in itself is not the problem, but the mapping of a collection of components. If you would map the component directly onto the Root class, this would not be any problem.
A possible workaround is making the Component class an entity (adding an ID) and overriding the mapping of Components to cascade + auto delete orphans:
AutoPersistenceModel
.ForTypesThatDeriveFrom<Root>(map => map.HasMany(root => root.Components).Cascade.AllDeleteOrphan())
Related
Here's the (edited) domain class:
public class Patient : IntegerKeyEntity
{
...
public virtual string LastName
{
get
{
return Encoding.Unicode.GetString(encryptionService.Decrypt(LastNameEncrypted));
}
set
{
LastNameEncrypted = encryptionService.Encrypt(value);
}
}
/// <summary>
/// Contains the encrypted last name. Access via LastName for unencrypted version.
/// </summary>
public virtual byte[] LastNameEncrypted { get; set; }
...
}
Here's the Fluent mapping:
public class PatientMap : ClassMap<Patient>
{
public PatientMap()
{
...
Map(x => x.LastNameEncrypted, "LastName")
.Not.Nullable();
...
}
}
I don't map LastName in Patient. The table has a LastName column (a varbinary) and no LastNameEncrypted column.
Here's the query:
public virtual IQueryable<TResult> SatisfyingElementsFrom(IQueryable<T> candidates, int start, int limit, string sort, string dir)
{
if (this.MatchingCriteria != null)
{
return candidates.Where(this.MatchingCriteria).OrderBy(sort + " " + dir).Skip(start).Take(limit).ToList().ConvertAll(this.ResultMap).AsQueryable();
}
return candidates.ToList().ConvertAll(this.ResultMap).AsQueryable();
}
The return (inside the if block) is where the error is triggered. The error says "Could not resolve property LastName of Patient".
I am using NHibernate (v2.1.2.4000), Fluent NHibernate (v1.1.0.685) and NHibernate.Linq (v1.1.0.1001). I cannot update these DLLs.
Is it because I don't have a mapping for Patient.LastName? I don't have or need one. If that is the issue, how do I map/tell Fluent NHibernate to ignore that property?
PS: I am not using AutoMapping, only explicit mappings. They are loaded as follows. In my application, only cfg (an NHibernate.Cfg.Configuration object) and mappingAssemblies (which points to the one DLL with the mappings) have a value.
private static ISessionFactory CreateSessionFactoryFor(string[] mappingAssemblies, AutoPersistenceModel autoPersistenceModel, Configuration cfg, IPersistenceConfigurer persistenceConfigurer)
{
FluentConfiguration fluentConfiguration = Fluently.Configure(cfg);
if (persistenceConfigurer != null)
{
fluentConfiguration.Database(persistenceConfigurer);
}
fluentConfiguration.Mappings(m =>
{
foreach (var mappingAssembly in mappingAssemblies)
{
var assembly = Assembly.LoadFrom(MakeLoadReadyAssemblyName(mappingAssembly));
m.HbmMappings.AddFromAssembly(assembly);
m.FluentMappings.AddFromAssembly(assembly).Conventions.AddAssembly(assembly);
}
if (autoPersistenceModel != null)
{
m.AutoMappings.Add(autoPersistenceModel);
}
});
return fluentConfiguration.BuildSessionFactory();
}
This error happens when you do the query. Looking to your code I see only one thing that might cause the problem - that is MatchingCriteria:
return candidates.Where(this.MatchingCriteria)...
What type is stored in this.MatchingCriteria?
Try to replace it with inline conditions: in
..Where(<put_inline_criteria_here>)..
EDIT I remade an entire project for this one problem. And thus, I remade the question.
I want to be able to efficiently avoid N+1 and Cartesian joins joining together a 4 level deep entity with a composite key on the third level.
I am looking for this to be done in only a few queries, not lazy loaded, and not just join all the tables together.
A -(many)-> B -(many)-> C -(composite, single)-> D
Something like:
Select * From A Left Join B On A.Id = B.AId
Select * From B Left Join C On B.Id = C.BId Inner Join D On C.DId = D.Id
Here is the code used
This is a fully functional app.
I used NuGet to install Sqlite x86, StructureMap, NHProf, Fluent NH.
StructureMapServiceLocator:
namespace MyTest.NHibernateTest
{
using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Practices.ServiceLocation;
using StructureMap;
public class StructureMapServiceLocator : ServiceLocatorImplBase
{
private readonly IContainer _container;
public StructureMapServiceLocator(IContainer container)
{
_container = container;
}
public IContainer Container { get { return _container; } }
protected override object DoGetInstance(Type serviceType, string key)
{
return string.IsNullOrEmpty(key)
? _container.GetInstance(serviceType)
: _container.GetInstance(serviceType, key);
}
protected override IEnumerable<object> DoGetAllInstances(Type serviceType)
{
return _container.GetAllInstances(serviceType).Cast<object>().AsEnumerable();
}
public override TService GetInstance<TService>()
{
return _container.GetInstance<TService>();
}
public override TService GetInstance<TService>(string key)
{
return _container.GetInstance<TService>(key);
}
public override IEnumerable<TService> GetAllInstances<TService>()
{
return _container.GetAllInstances<TService>();
}
}
}
AppRegistry
namespace MyTest.NHibernateTest
{
using System;
using System.Collections.Generic;
using System.Linq;
using StructureMap.Configuration.DSL;
using FluentNHibernate.Cfg.Db;
using FluentNHibernate.Cfg;
using NHibernate;
using NHibernate.Tool.hbm2ddl;
using FluentNHibernate.Automapping;
using FluentNHibernate.Data;
public class AppRegistry : Registry
{
public AppRegistry()
{
var dbConfiguration = SQLiteConfiguration.Standard
.ConnectionString("Data Source=sqlite.db;Version=3;New=True;");
dbConfiguration.ShowSql();
var cfg = Fluently.Configure()
.Database(dbConfiguration)
.Mappings(m =>
{
m.AutoMappings.Add(AutoMap.AssemblyOf<Program>().Where(t =>
{
return typeof(Entity).IsAssignableFrom(t);
}));
})
.ExposeConfiguration(c =>
{
if (RebuildSchema.Value)
new SchemaExport(c).Create(false, true);
});
var sessionFactory = cfg.BuildSessionFactory();
For<ISessionFactory>().Singleton().Use(sessionFactory);
For<ISession>().HybridHttpOrThreadLocalScoped().Use(cx =>
{
var session = cx.GetInstance<ISessionFactory>().OpenSession();
session.FlushMode = FlushMode.Commit;
return session;
});
}
}
}
Listing Entities:
namespace MyTest.NHibernateTest.Entities
{
using System;
using System.Collections.Generic;
using System.Linq;
using FluentNHibernate.Data;
public class Listing : Entity
{
public Listing()
{
Items = new List<ListingItem>();
}
public virtual IList<ListingItem> Items { get; set; }
}
public class ListingItem : Entity
{
public ListingItem()
{
Values = new List<ListingItemValue>();
}
public virtual IList<ListingItemValue> Values { get; set; }
}
public class ListingItemValue : Entity
{
public virtual ListingItem ListingItem { get; set; }
public virtual ListingItemField ListingItemField { get; set; }
}
public class ListingItemField : Entity
{
public virtual string Value { get; set; }
}
}
Program (console):
namespace MyTest.NHibernateTest
{
using System;
using System.Collections.Generic;
using System.Linq;
using StructureMap;
using HibernatingRhinos.Profiler.Appender.NHibernate;
using Microsoft.Practices.ServiceLocation;
using NHibernate;
using System.Threading;
using NHibernate.Transform;
using MyTest.NHibernateTest.Entities;
public static class RebuildSchema
{
public static bool Value { get; set; }
}
class Program
{
static void Main(string[] args)
{
RebuildSchema.Value = true;
Setup();
BuildData();
Work();
Console.ReadLine();
}
static void Setup()
{
NHibernateProfiler.Initialize();
ObjectFactory.Initialize(x =>
{
x.Scan(s =>
{
s.TheCallingAssembly();
s.LookForRegistries();
});
});
ServiceLocator.SetLocatorProvider(() => new StructureMapServiceLocator(ObjectFactory.Container));
}
static void BuildData()
{
var s = ObjectFactory.GetInstance<NHibernate.ISession>();
using (var t = s.BeginTransaction())
{
var listing = new Listing();
s.Save(listing);
var item = new ListingItem();
listing.Items.Add(item);
s.Save(item);
var item2 = new ListingItem();
listing.Items.Add(item2);
s.Save(item2);
var field = new ListingItemField();
field.Value = "A";
s.Save(field);
var field2 = new ListingItemField();
field2.Value = "B";
s.Save(field2);
var value = new ListingItemValue();
value.ListingItem = item;
value.ListingItemField = field;
item.Values.Add(value);
s.Save(value);
var value2 = new ListingItemValue();
value2.ListingItem = item;
value2.ListingItemField = field2;
item.Values.Add(value2);
s.Save(value2);
var value3 = new ListingItemValue();
value3.ListingItem = item2;
value3.ListingItemField = field;
item2.Values.Add(value3);
s.Save(value3);
t.Commit();
}
}
static void Work()
{
var s = ObjectFactory.GetInstance<ISession>();
IList<Listing> foo;
using (var t = s.BeginTransaction())
{
foo = s.QueryOver<Listing>()
.Left.JoinQueryOver<ListingItem>(x => x.Items)
.Left.JoinQueryOver<ListingItemValue>(x => x.Values)
.Left.JoinQueryOver<ListingItemField>(x => x.ListingItemField)
.TransformUsing(Transformers.DistinctRootEntity)
.List();
t.Commit();
}
try
{
Thread.Sleep(100);
var x1 = foo[0];
Thread.Sleep(100);
var x2 = x1.Items[0];
Thread.Sleep(100);
var x3 = x2.Values[0];
Thread.Sleep(100);
var x4 = x2.Values[0].ListingItemField.Value;
}
catch (Exception) { }
}
}
}
Can you please provide details of your mapping. One method to reduce the number of queries (not to one, but to very few) would be to use the batch-size feature in your mapping. That would populate the proxies on way fewer roundtrips than N+1. But really there should be a solution to fetch all data using futures or similar, so please provide mapping.
This is what I usually do:
First of all, are you familiar with .Future() and .FutureValue()? With those you can send several queries in a single roundtrip. It's only two queries here, so it's not big of a deal, but still...
What I am trying to do is:
Prefetch all ListingItems and their Values and Fields to the first level cache so that they don't trigger Lazy Loading. As you can see I don't use a variable in the first query, because I don't need to store the result. I just need for this query to run and 'prefetch' my entities.
I could avoid the Subquery part, but the Subquery helps me avoiding a cartesian product between Listings - Items - Values.
Since each Value has a single Field, I won't have a problem, in the second query, with a cartesian product.
Then, just get the Listing, along with its Items. The .Value; part with trigger the 'execution' of both queries in a single roundtrip to the database.
The result should be this. As I travel through the object graph, all objects should be already in first level cache and no lazy loading should happen.
.
using (var t = s.BeginTransaction())
{
ListingItem liAlias = null
ListingItemValue livAlias = null;
// 'Preload' all ListingItems with their Values and Fields
s.QueryOver<ListingItem>()
.JoinAlias(li => li.Values, () => livAlias, JoinType.LeftOuterJoin)
.Fetch(_ => livAlias.ListingItemField).Eager
.WithSubquery.WhereProperty(li => li.Id).In(
QueryOver.Of<Listing>()
.Where(l => l.Id == id)
.JoinAlias(l => l.Items, () => liAlias, JoinType.LeftOuterJoin)
.Select(_ => liAlias.Id)
)
.Future();
// Get a single Listing w/ all its Items
var listing = s.QueryOver<Listing>()
.Fetch(l => l.Items).Eager
.Where(l => l.Id == id)
.FutureValue()
.Value;
t.Commit();
}
I have to say here that I haven't tested that, so possibly I am missing something. Secondly, I didn't take in account the composite key you mention. I don't know if that will causes any issues, but I can't see why it should.
Please try it out and let me know.
I want to upgrade my application to use NHiberante 3 instead of NHibernate 2.1.2 but faced some problems with the new LINQ provider. This question is about one of them. Assume that I have a following hierarchy of classes:
public abstract class PageData
{
public int ID { get; set; }
public string Title { get; set; }
}
public class ArticlePageData : PageData
{
public DateTime PublishedDate { get; set; }
public string Body { get; set; }
}
public class ExtendedArticlePageData : ArticlePageData
{
public string Preamble { get; set; }
}
I use Fluent NHibernate to map these classes to the database:
public class PageDataMap : ClassMap<PageData>
{
public PageDataMap()
{
Table("PageData");
Id(x => x.ID);
Map(x => x.Title);
DiscriminateSubClassesOnColumn("PageType");
}
}
public class ArticlePageDataMap : SubclassMap<ArticlePageData>
{
public ArticlePageDataMap()
{
Join("ArticlePageData", p =>
{
p.KeyColumn("ID");
p.Map(x => x.PublishedDate);
p.Map(x => x.Body);
});
}
}
public class ExtendedArticlePageDataMap : SubclassMap<ExtendedArticlePageData>
{
public ExtendedArticlePageDataMap ()
{
Join("ExtendedArticlePageData", p =>
{
p.KeyColumn("ID");
p.Map(x => x.Preamble);
});
}
}
And then I want to query all pages and do some filtering:
IQueryable<PageData> pages = session.Query<PageData>();
...
var articles = pages.OfType<ArticlePageData>().Where(x => x.PublishedDate >= (DateTime.Now - TimeSpan.FromDays(7))).ToList();
NHibernate 3.0.0 fails with the NotSupported exception in this case, but there is bugfix NH-2375 in the developing version of NH which leads this code to work. But, unfortunately, OfType() method filters the objects by exact type and only selects objects of ArticlePageData class. The old Linq to NH provider selects ArticlePageData and ExtendedArticlePageData in the same case.
How can I do such filtering (select only objects of class T and its subclasses) with the new Linq to NH provider?
session.Query<T>().OfType<SubT>() makes little sense, and it won't let you filter on properties of the subclass. Use session.Query<SubT>() instead.
You can use
var articles = pages.AsEnumerable().OfType<ArticlePageData>().Where(x => x.PublishedDate >= (DateTime.Now - TimeSpan.FromDays(7))).ToList();
and wait for NHibernate 3.0.1.
or maybe you can use
session.Query<ArticlePageData>()
instead of
session.Query<PageData>()
Does anyone know how can we automatically map dynamic components using Fluent Automapping in NHibernate?
I know that we can map normal classes as components, but couldn't figure out how to map dictionaries as dynamic-components using fluent automapping.
Thanks
We've used the following approach successfully (with FluentNH 1.2.0.712):
public class SomeClass
{
public int Id { get; set; }
public IDictionary Properties { get; set; }
}
public class SomeClassMapping : ClassMap<SomeClass>
{
public SomeClassMapping()
{
Id(x => x.Id);
// Maps the MyEnum members to separate int columns.
DynamicComponent(x => x.Properties,
c =>
{
foreach (var name in Enum.GetNames(typeof(MyEnum)))
c.Map<int>(name);
});
}
}
Here we've mapped all members of some Enum to separate columns where all of them are of type int. Right now I'm working on a scenario where we use different types for the dynamic columns which looks like this instead:
// ExtendedProperties contains custom objects with Name and Type members
foreach (var property in ExtendedProperties)
{
var prop = property;
part.Map(prop.Name).CustomType(prop.Type);
}
This also works very well.
What I'm still about to figure out is how to use References instead of Map for referencing other types that have their own mapping...
UPDATE:
The case with References is unfortunately more complicated, please refer to this Google Groups thread. In short:
// This won't work
foreach (var property in ExtendedProperties)
{
var prop = property;
part.Reference(dict => dict[part.Name]);
}
// This works but is not very dynamic
foreach (var property in ExtendedProperties)
{
var prop = property;
part.Reference<PropertyType>(dict => dict["MyProperty"]);
}
That's all for now.
I got struggle with exactly the same problem. With fluent nHibernate we cannot map this but on my own I somehow was able to solve this. My solution is to build lambda expression on the fly and the assign this into object. For instance, lets say that:
Let my copy part of the site that Oliver refer:
DynamicComponent(
x => x.Properties,
part =>
{
// Works
part.Map("Size").CustomType(typeof(string));
// Works
var keySize = "Size";
part.Map(keySize).CustomType(typeof(string));
// Does not work
part.Map(d => d[keySize]).CustomType(typeof(string));
// Works
part.References<Picture>(d => d["Picture"]);
// Does not work
var key = "Picture";
part.References<Picture>(d => d[key]);
});
And we have this problem that we need to hardcode "Picture" in mapping. But somehow after some research I created following solution:
var someExternalColumnNames = GetFromSomewhereDynamicColumns();
'x' is a DynamicComponent callback in fluent Nhibernate e.g. (DynamicColumns): DynamicComponent(a => a.DynamicColumns, x => (...content of method below...))
foreach(var x in someExternalColumnNames)
{
if (x.IsReferenceToPerson == true)
{
var param = Expression.Parameter(typeof(IDictionary), "paramFirst");
var key = Expression.Constant(x.Name);
var me = MemberExpression.Call(param, typeof(IDictionary).GetMethod("get_Item"), new[] { key });
var r = Expression.Lambda<Func<IDictionary, object>>(me, param);
m.References<Person>(r, x.Name);
}
else
{
m.Map(x.Name)
}
}
//
// Some class that we want to reference, just an example of Fluent Nhibernate mapping
public class PersonMap : ClassMap<Person>
{
public PersonMap()
{
Table("Person");
Id(x => x.PersonId, "PersonId");
Map(x => x.Name);
}
}
public class Person
{
public virtual Guid PersonId { get; set; }
public virtual string Name { get; set; }
public Person()
{ }
}
Maybe it would be helpful
I define a simple Bug Class:
using System;
namespace BugNS.Entities
{
class Bug
{
public virtual int Id { get; private set; }
public virtual int BugNumber { get; set; }
}
}
and a simple mapper class:
using System;
using FluentNHibernate.Mapping;
using BugNS.Entities;
namespace BugNS.Mappings
{
class BugMap : ClassMap<Bug>
{
public BugMap()
{
Id(b => b.Id);
Map(b => b.BugNumber);
}
}
}
and then just try to use it like:
using System;
using System.IO;
using FluentNHibernate.Cfg;
using FluentNHibernate.Cfg.Db;
using NHibernate;
using NHibernate.Cfg;
using NHibernate.Tool.hbm2ddl;
using BugNS.Entities;
namespace BugNS
{
class Program
{
private const string DbFile = "bugs.db";
static void Main()
{
var sessionFactory = CreateSessionFactory();
using (var session = sessionFactory.OpenSession())
{
using (var transaction = session.BeginTransaction())
{
Bug b = new Bug { BugNumber = 121212 };
session.SaveOrUpdate(b);
transaction.Commit();
}
}
}
private static ISessionFactory CreateSessionFactory()
{
return Fluently.Configure()
.Database(SQLiteConfiguration.Standard
.UsingFile(DbFile))
.Mappings(m =>
m.FluentMappings.AddFromAssemblyOf<Program>())
.ExposeConfiguration(BuildSchema)
.BuildSessionFactory();
}
private static void BuildSchema(Configuration config)
{
// delete the existing db on each run
if (File.Exists(DbFile))
File.Delete(DbFile);
// this NHibernate tool takes a configuration (with mapping info in)
// and exports a database schema from it
new SchemaExport(config)
.Create(false, true);
}
}
}
and I got the following error:
An unhandled exception of type
'NHibernate.MappingException' occurred
in NHibernate.dll
Additional information: No persister
for: BugNS.Entities.Bug
I am sorry, but I just started learning Fluent and NHibernate from the docs. It would be great if someone knows the solution to this issue, as I already spend many hours in vain.
Access level of the class needs to be public for Fluent to make use of it.
Try the following:
public class Bug
{
public virtual int Id { get; private set; }
public virtual int BugNumber { get; set; }
}
public class BugMap : ClassMap<Bug>
{
public BugMap()
{
Id(b => b.Id);
Map(b => b.BugNumber);
}
}
This is a gotcha for me as well when I started using Fluent.
One more thing that generally goes wrong is missing out virtual keyword, which is needed for NHibernate to make changes to those properties. Its nice that you made that part correct :)
Hope that helps.
Thanks
You need to make the Bug and BugMap classes public so that NHibernate/Fluent NHibernate can see them.