I am working on NET MVC 3.0 and Nhibernate 3.0. I want to fetch only one property from database to an object.
For instance, suppose I have a class Module. I want to select all the names from module table (like select modulename from module query) and an prepare a list of module objects which have only name. All other properties can be null.
I tried this using QueryOver API:
IQueryOver<ProjectModule> module = session.QueryOver<ProjectModule>()
.Select(a=>a.Name)
.TransformUsing(
NHibernate.Transform.Transformers.AliasToBean<ProjectModule>());
pm = module.List<ProjectModule>();
pm is IList<ProjectModule> type.
Transaction gets committed successfully. No error occurred, but I get a list of module objects with all properties = null. Module name null, module id null etc.
I checked what query is executing on SQL using NUnit and got this: SELECT this_Name as y0_ FROM ProjectModule this_.
To be more accurate create a DTO object, assume ProjectModuleDto, that will contain only the Name. It's not a good practice to use the the domain object with uninitialized values through your code, cause it creates confusions of filled data in various scenarious.
And the fllowing code will do the trick - populate the list of DTOs: ProjectModuleDto with correct Name of project module from database:
ProjectModuleDto projectModuleDto = null;
IQueryOver<ProjectModule> module = session.QueryOver<ProjectModule>()
.SelectList(
list=>list.Select(a => a.Name).WithAlias(() => projectModuleDto.Name)
)
TransformUsing(NHibernate.Transform.Transformers.AliasToBean<ProjectModuleDto>());
pm = module.List<ProjectModuleDto>();
If you are fetching only a single property, you don't need to use transformers. Try to use a List<string> directly:
var moduleNames = session.QueryOver<ProjectModule>()
.Select(a => a.Name)
.List<string>();
Read more about QueryOver syntax on NHibernate blog.
Is this what you're looking for?
List<ProjectModule> result = new List<ProjectModule>();
session.QueryOver<ProjectModule>()
.Select(a => a.Name)
.ToList().ForEach(delegate(string mName)
{
result.Add(ProjectModule() { Name = mName });
});
Related
I'm trying to use RepoDb to query the contents of a table (in an existing Sql Server database), but all my attempts result in an InvalidOperationException (There are no 'contructor parameter' and/or 'property member' bindings found between the resultset of the data reader and the type 'MyType').
The query I'm using looks like the following:
public Task<ICollection<MyType>> GetAllAsync()
{
var result = new List<MyType>();
using (var db = new SqlConnection(connectionString).EnsureOpen())
{
result = (await db.ExecuteQueryAsync<MyType>("select * from mytype")).ToList();
}
return result;
}
I'm trying to run this via a unit test, similar to the following:
[Test]
public async Task MyTypeFetcher_returns_all()
{
SqlServerBootstrap.Initialize();
var sut = new MyTypeFetcher("connection string");
var actual = await sut.GetAllAsync();
Assert.IsNotNull(actual);
}
The Entity I'm trying to map to matches the database table (i.e. class name and table name are the same, property names and table column names also match).
I've also tried:
putting annotations on the class I am trying to map to (both at the class level and the property level)
using the ClassMapper to map the class to the db table
using the FluentMapper to map the entire class (i.e. entity-table, all columns, identity, primary)
putting all mappings into a static class which holds all mapping and configuration and calling that in the test
providing mapping information directly in the test via both ClassMapper and FluentMapper
From the error message it seems like RepoDb cannot find the mappings I'm providing. Unfortunately I have no idea how to go about fixing this. I've been through the documentation and the sample tutorials, but I haven't been able to find anything of use. Most of them don't seem to need any mapping configuration (similar to what you would expect when using Dapper). What am I missing, and how can I fix this?
I'm using early-bound entities, generated by CrmSvcUtil, and I'm testing the SDK by retrieving an account entity:-
var account = myContext.AccountSet.FirstOrDefault(o => o.Id == Guid.Parse("..."));
(BTW is there an easier way to retrieve an entity by ID?!)
Looking at the account object that is returned, I can see various properties of type OptionSetValue (e.g. "PreferredContactMethodCode"). How do I get the actual item from this OptionSetValue object?
Similarly, there are numerous properties of type EntityReference, which contains an Id and LogicalName (the entity name I presume). How can I populate such a property - is it one of the Get... methods? And do these have to be called separately, or is it possible to "pre-fetch" certain relationships as part of the initial query that retrieves the account entity?
Similarly with the various IEnumerable<> properties (which presumably correspond to 1-M entity relationships), e.g. a property called "opportunity_customer_accounts" of type IEnumerable. How do I populate one of these properties? And (again) does this have to be done as a separate query/method call, or can it be "pre-fetched"?
Retrieve
I'm not really sure how much simpler the retrieve operation could get but for a single record the user of the context is probably overkill. So you could retrieve a specific record where you know directly with the IOrganizationService:
account = service.Retrieve("account", Guid.Parse("..."), new ColumnSet(true));
Option Set Labels
For the OptionSet labels you can look at my answer here: How to get the option set from a field in an entity in CRM 2011 using crm sdk and C#.
If you need the label for multiple OptionSet's on an entity you may want to just retrieve the Entity's metadata once (http://srinivasrajulapudi.blogspot.com/2012/01/retrieve-entity-metadata-in-crm-2011.html):
string entityName ="contact";
// Get the metadata for the currently list's entity
// This metadata is used to create a "Property Descriptor Collection"
RetrieveEntityRequest mdRequest = new RetrieveEntityRequest ( )
{ EntityFilters = EntityFilters.All,
LogicalName = entityName,
RetrieveAsIfPublished = false
};
// Execute the request
RetrieveEntityResponse entityResponse = ( RetrieveEntityResponse ) this.ServiceProxy.Execute ( mdRequest );
EntityMetadata entityData = entityResponse.EntityMetadata;
//To Get Option Set Data
var preferdList= ( entityData.Attributes.Where ( p => p.LogicalName == "preferredcontactmethodcode" ) ).ToList ( ).FirstOrDefault ( ); ;
if ( preferdList != null ) {
PicklistAttributeMetadata optionList= preferdList as PicklistAttributeMetadata;
OptionSetMetadata opValues= optionList.OptionSet;
foreach ( var op in opValues.Options ) {
preferedMethod.Add ( new OptionSet { Value = op.Value.Value, Text = op.Label.LocalizedLabels[0].Label.ToString() } );
}
}
EntityReference()
To set an EntityReference typed field:
account.primarycontact = new EntityReference("contact", Guide.Parse("..."));
If they have a value and you requested the column in your ColumnSet() they should be populated, so I'm not really sure I understand your question. If you mean, you want the full record then you need to do a service.Retrieve(...) for the record.
Related Entities (i.e., opportunity_customer_accounts)
This is where using an OrganizationServiceContext makes life easier (https://msdn.microsoft.com/en-us/library/gg695791.aspx):
context.LoadProperty(contact, "transactioncurrency_contact");
// read related entity dynamically
var currency = contact.GetRelatedEntity("transactioncurrency_contact");
Console.WriteLine(currency.GetAttributeValue("currencyname"));
// read related entity statically
var currencyStatic = contact.transactioncurrency_contact;
Console.WriteLine(currencyStatic.CurrencyName);
If you are not using an OrganizationServiceContext you can try using a QueryExpression using LinkedEntities, although I've never done this to populate an early-bound entity so I don't know if it works (perhaps someone will add a comment with the answer.)
I am trying to get a QueryOver working using a Projection on a many-to-one.
The class "Post" has a property many-to-one "Creator".
Using
session.QueryOver(Of Post).
Select(Projections.
Property(of Post)(Function(x) x.Creator).
WithAlias(Function() postAlias.Creator)).
TransformUsing(Transformers.AliasToBean(Of Post)()).
List()
works BUT each creator is retrieved by a single query rather than using a join like it is done when not using a select/projection. So if there are 5 posts with 5 different creators, 6 queries will be run 1 for the list of posts and 5 for the creators.
I tried to get it working using a JoinAlias but nothing really did the job.
I already searched for a solution, but all solutions I found did use the Linq-Provider which does not really fit since the actual "field list" is passed via a parameter.
Does anyone know if there is a solution to this other than the linq provider?
There is a solution, we can use projections for many-to-one and then custom result transformer.
DISCLAIMER: I can read VB syntax but do not have enough courage to write... I expect that you can read C# and convert it into VB....
So we can have projection like this:
// aliases
Post root = null;
Creator creator = null;
// projection list
var columns = Projections.ProjectionList();
// root properties
columns.Add(Projections.Property(() => root.ID).As("ID"));
columns.Add(Projections.Property(() => root.Text).As("Text"));
// reference properties
columns.Add(Projections.Property(() => creator.ID).As("Creator.ID"));
columns.Add(Projections.Property(() => creator.FirstName).As("Creator.FirstName"));
// so our projections now do have proper ALIAS
// alias which is related to domain model
// (because "Creator.FirstName" will be use in reflection)
var query = session.QueryOver<Post>(() => root)
.JoinAlias(() => root.Creator, () => creator)
.Select(columns)
Now we would need smart Transformer, our own custome one (plugability is power of NHibernate). Here you can find one:
public class DeepTransformer
And we can continue like this
var list = query
.TransformUsing(new DeepTransformer<Post>())
.List<Post>()
Check also this:
Fluent NHibernate - ProjectionList - ICriteria is returning null values
NHibernate AliasToBean transformer associations
In my BreezeController I have a method that returns a DTO with two properties. One property is a navigation property to one of my entities, and the other a boolean:
Public Function ProjectList() As IQueryable
Return From p In _contextProvider.Context.Projects
Where Not p.IsDeleted
Select New ProjectListItem() With {
.Project = p,
.HasTasks = (From t In _contextProvider.Context.ProjectTasks Where t.ProjectID = p.ID).Any()
}
End Function
Public Class ProjectListItem
Public Property Project As Project
Public Property HasTasks As Boolean
End Class
Simple queries against this method work fine, but my Project class has a collection of project managers, and using an "any" query against this collection is failing in the Breeze client code, before sending the query to the server, with the following error message:
Exception was thrown at line 10698, column 13 in http://localhost:2780/myapp/Scripts/breeze.debug.js
0x800a138f - JavaScript runtime error: Unable to get property 'isAnonymous' of undefined or null reference
This is in the proto._validate method of FnNode, where entityType is null.
My query (I'm trying to find all projects for a specific project manager) is built up in pieces, but the relevant parts are:
var p = breeze.Predicate.create("ProjectManagerID", op.Equals, id);
var predicate = breeze.Predicate.create("Project.ProjectManagers", "any", p);
// code common to all queries...
var query = breeze.EntityQuery.from("ProjectList");
query = query.where(predicate);
query = query.select("Project.Prop1,Project.Prop2,Project.etc,HasTasks");
return query.using(this.manager).execute();
I create other predicates and run them through the same common logic and they work fine, so it seems to be limited to "any" queries, e.g. this one works...
predicate = breeze.Predicate.create("Project.ClientNumber", op.Contains, search)
.or("Project.ClientName", op.Contains, search)
.or("Project.Notes", op.Contains, search);
I am still using Breeze 1.4.16 (WebAPI v1, .NET 4.0), but have tried updating the Breeze.Client package to 1.5.1, which makes no difference.
Any ideas what I'm doing wrong?
If I manually build the OData query I am looking for, then I get the results that I want, e.g.
http://localhost:1234/myApp/breeze/myController/ProjectList?$filter=Project/ProjectManagers/any(p:p/ProjectManagerID eq 234)&$select=Project/Prop1,Project/Prop2,HasTasks
After you have setup your mappings in fluent nhibernate, is there a way of getting the table name for an entity from the class type?
I have read in regular nhiberante you can do something like cfg.GetClassMapping(typeof (Employee)). I would like to do the type of thing to retrieve the database table name.
Is this possible as standard or how would I go about this?
The fluent nhibernate way:
var userMetadata = sessionFactory.GetClassMetadata(typeof(SomeEntity)) as NHibernate.Persister.Entity.AbstractEntityPersister;
var cols = userMetadata.KeyColumnNames;
var table = userMetadata.TableName;
where sessionFactory is of type ISessionFactory.
Assuming you have done this at some point:
FluentNHibernate.Cfg.FluentConfiguration fluentConfig = FluentNHibernate.Cfg.Fluently.Configure();
Then all you have to do is this:
string tableName = fluentConfig.BuildConfiguration().GetClassMapping(typeof (One of your data entities)).Table.Name;
Worked great in my implementation of a generic "GetAllItems" routine.
Hi I'm using this to create Full Text Catalogs on M$ Sql Server, using almost same mechanism of FluentNhibernate mapping.
From Configuration I get a list of persistentClasses
this.persistenClasses = configuration.ClassMappings;
Next I search through this list to find my persistenClass class by its Generic type of mapping class
var genericDefinition = mappingClass.BaseType.GetGenericArguments()[0];
var matchedPersistClass = FindPersistedClassFrom(genericDefinition);
private PersistentClass FindPersistedClassFrom(Type genericDefinition)
{
return persistentClasses.FirstOrDefault(x => x.EntityName == genericDefinition.FullName);
}
So having persistentClass you easily have access to Table Name, properties, db fields, etc.
TableName = matchedPersistClass.Table.Name,
cfg.GetClassMapping(typeof(Employee)).Table.Name will also work, and seems to be much simpler.