I want to retrieve an object plus its filtered/ordered collection property using EF 5. However, my current code throws an exception:
The Include path expression must refer to a navigation property
defined on the type. Use dotted paths for reference navigation
properties and the Select operator for collection navigation
properties
Here is the class of the object I want to retrieve:
public class EntryCollection
{
[Key]
public int Id { get; set; }
public ICollection<Entry> Entries { get; set; }
...
}
And here is the definition of Entry:
public class Entry
{
[Key]
public int Id { get; set; }
public DateTime Added { get; set; }
...
}
I wanted to retrieve the EntryCollection which contains only the most recent entries, so here is the code I tried:
using (var db = new MyContext())
{
return db.EntryCollections
.Include(ec => ec.Entries.OrderByDescending(e => e.Added).Take(5))
.SingleOrDefault(ec => ec.Foo == "bar');
}
Any ideas?
You cant use OrderBy inside an include.
what about the following
using (var db = new MyContext())
{
return db.EntryCollections
.Where(ec => ec.Foo == "bar")
.Select(ec=> new Something{Entries = ec.Entries.OrderByDescending(e => e.Added).Take(5) }, /*some other properties*/)
.SingleOrDefault();
}
or do it in two seperate queries
Related
In my EF Core solution I have the following model:
public class Deal
{
public string Id { get; set; }
public ResponsiblePerson ResponsiblePerson1 { get; set; }
public ResponsiblePerson ResponsiblePerson2 { get; set; }
public ResponsiblePerson ResponsiblePerson3 { get; set; }
}
public class ResponsiblePerson
{
public string Id { get; set; }
public string Name { get; set; }
}
When I am trying to update Deal navigations properties:
private void UpdateResponsiblePersons(string dealId, string person1Id, string person2Id, string person3Id)
{
var existingdeal = _dbContext.Deals
.Include(d => d.ResponsiblePerson1)
.Include(d => d.ResponsiblePerson2)
.Include(d => d.ResponsiblePerson3)
.Single(d => d.Id == dealId);
existingDeal.ResponsiblePerson1 = new ResponsiblePerson { Id = person1Id };
existingDeal.ResponsiblePerson2 = new ResponsiblePerson { Id = person2Id };
existingDeal.ResponsiblePerson3 = new ResponsiblePerson { Id = person3Id };
_dbContext.Entry(deal.ResponsiblePerson1).State = EntityState.Unchanged;
_dbContext.Entry(deal.ResponsiblePerson3).State = EntityState.Unchanged;
_dbContext.Entry(deal.ResponsiblePerson3).State = EntityState.Unchanged;
_dbContext.SaveChanges();
}
EF often fails with
System.InvalidOperationException: The instance of entity type 'ResponsiblePerson' cannot be tracked because another instance with the key value '{Id: 1}' is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached.
That is because sometimes existingdeal already contains the link to ResponsiblePerson with one of provided IDs in either ResponsiblePerson1 of ResponsiblePerson2 or ResponsiblePerson3 Navigation properties.
I know that one of possible solutions will be first to get ResponsiblePersons used for update from dbContext like
existingDeal.ResponsiblePerson1 = _dbContext.ResponsiblePersons.Find(person1Id)
But that means extra DB roundtrips.
Another solution is to expose foreign keys instead of navigation properties but it would make Deal model quite ugly.
Please advice me what is the best way of updating such references?
What I would like to do is duplicate/copy my School object and all of its children/associations in EF Core
I have something like the following:
var item = await _db.School
.AsNoTracking()
.Include(x => x.Students)
.Include(x => x.Teachers)
.Include(x => x.StudentClasses)
.ThenInclude(x => x.Class)
.FirstOrDefaultAsync(x => x.Id == schoolId);
I have been reading up on deep cloning and it seems that I should be able to do just add the entity...so pretty much the next line.
await _db.AddAsync(item);
Then EF should be smart enough to add that entity as a NEW entity. However, right off the bat I get a conflict that says "the id {schoolId} already exists" and will not insert. Even if I reset the Id of the new item I am trying to add, I still get conflicts with the Ids of the associations/children of the school iteam.
Is anyone familiar with this and what I might be doing wrong?
I had the same problem too, but in my case EF core was throwing exception "the id already exists".
Following the answer of #Irikos so I have created method which clones my objects.
Here's example
public class Parent
{
public int Id { get; set; }
public string SomeProperty { get; set; }
public virtual List<Child> Templates { get; set; }
public Parent Clone()
{
var output = new Parent() { SomeProperty = SomeProperty };
CloneTemplates(output);
return output;
}
private void CloneTemplates(Parent parentTo, Child oldTemplate = null, Child newTemplate = null)
{
//find old related Child elements
var templates = Templates.Where(c => c.Template == oldTemplate);
foreach (var template in templates)
{
var newEntity = new Child()
{
SomeChildProperty = template.SomeChildProperty,
Template = newTemplate,
Parent = parentTo
};
//find recursivly all related Child elements
CloneTemplates(parentTo, template, newEntity);
parentTo.Templates.Add(newEntity);
}
}
}
public class Child
{
public int Id { get; set; }
public int ParentId { get; set; }
public virtual Parent Parent { get; set; }
public int? TemplateId { get; set; }
public virtual Child Template { get; set; }
public string SomeChildProperty { get; set; }
}
Then I just call DbContext.Parents.Add(newEntity) and DbContext.SaveChanges()
That worked for me. Maybe this will be useful for someone.
I had the same problem, but in my case, ef core was smart enough save them as new entities even with existing id. However, before realising that, I just made a copy constructor for all the items, created a local task variable containing only the desired properties and returned the copy.
Remove certain properties from object upon query EF Core 2.1
Im trying to save a rating against a place, I have the code below, but it doesnt seems to save rating (to the ratings table) for an existing entity
place.Ratings.Add(rating);
_placeRepository.AddPlaceIfItDoesntExist(place);
_placeRepository.Save();
This is the repository method
public void AddPlaceIfItDoesntExist(Place place)
{
var placeItem = context.Places.FirstOrDefault(x => x.GooglePlaceId == place.GooglePlaceId);
if(placeItem==null)
{
context.Places.Add(place);
}
else
{
context.Entry(placeItem).State = EntityState.Modified;
}
}
and this is the poco
public class Place
{
public Place()
{
Ratings = new List<Rating>();
}
public int Id { get; set; }
public string Name { get; set; }
public string GooglePlaceId { get; set; }
}
I think the crux of the problem is because i need to check if the place exists based on googleplaceid(a string) rather than the id (both are unique per place btw)
Here
context.Entry(placeItem).State = EntityState.Modified;
you just mark the existing placeItem object as modified. But it's a different instance than the passed place object, hence contains the orginal values.
Instead, replace that line with:
context.Entry(placeItem).CurrentValues.SetValues(place);
Alternatively, you can use the DbSetMigrationsExtensions.AddOrUpdate method overload that allows you to pass a custom identification expression:
using System.Data.Entity.Migrations;
public void AddPlaceIfItDoesntExist(Place place)
{
context.Places.AddOrUpdate(p => p.GooglePlaceId, place);
}
I am in the process of creating a domain model and would like to have a "BaseEntity" class with an "Id" property (and some other audit tracking stuff). The Id property is the primary key and each Entity in my Domain Model will inherit from the BaseEntity class. Pretty straightforward stuff.....
public class BaseEntity
{
[Key]
public int Id { get; set; }
public DateTime LastUpdate { get; set; }
public string LastUpdateBy { get; set; }
}
public class Location : BaseEntity
{
[Required]
public string Name { get; set; }
public string Description { get; set; }
}
Using the example above, I would like to map the "Id" field to a "LocationId" column. I understand that I can use the modelBuilder to do this for each entity explicitly by doing something like this:
modelBuilder.Entity<Location>().Property(s => s.Id).HasColumnName("LocationId");
But I would like to do this for every Entity in my domain model and it would be ugly.
I tried the following bit of reflection but did not have any luck. For whatever reason, the compiler "cannot resolve symbol type":
foreach (var type in GetTypesInNamespace(Assembly.Load("Domain.Model"),"Domain.Model"))
{
modelBuilder.Entity<type>().Property(x=>x.Id).....
}
Is there a way to define a convention to override the default PrimaryKey convention to map my "Id" property to a "ClassNameId" property in the database? I am using Entity Framework 6.
You should take a look at Custom Code First Conventions. You need EF6 for it to work, but it looks like you're already using it.
Just to give you an overview, take a look at the following convention I've used to convert PascalCase names to underscore names. It includes a convention for id properties... It also includes an optional table name prefix.
public class UnderscoreNamingConvention : IConfigurationConvention<PropertyInfo, PrimitivePropertyConfiguration>,
IConfigurationConvention<Type, ModelConfiguration>
{
public UnderscoreNamingConvention()
{
IdFieldName = "Id";
}
public string TableNamePrefix { get; set; }
public string IdFieldName { get; set; }
public void Apply(PropertyInfo propertyInfo, Func<PrimitivePropertyConfiguration> configuration)
{
var columnName = propertyInfo.Name;
if (propertyInfo.Name == IdFieldName)
columnName = propertyInfo.ReflectedType.Name + IdFieldName;
configuration().ColumnName = ToUnderscore(columnName);
}
public void Apply(Type type, Func<ModelConfiguration> configuration)
{
var entityTypeConfiguration = configuration().Entity(type);
if (entityTypeConfiguration.IsTableNameConfigured) return;
var tableName = ToUnderscore(type.Name);
if (!string.IsNullOrEmpty(TableNamePrefix))
{
tableName = string.Format("{0}_{1}", TableNamePrefix, tableName);
}
entityTypeConfiguration.ToTable(tableName);
}
public static string ToUnderscore(string value)
{
return Regex.Replace(value, "(\\B[A-Z])", "_$1").ToLowerInvariant();
}
}
You use it like this
modelBuilder.Conventions.Add(new UnderscoreNamingConvention { TableNamePrefix = "app" });
EDIT: In your case, the Apply method should be something like this:
public void Apply(PropertyInfo propertyInfo, Func<PrimitivePropertyConfiguration> configuration)
{
if (propertyInfo.Name == "Id")
{
configuration().ColumnName = propertyInfo.ReflectedType.Name + "Id";
}
}
Try this out in your DbContext class;
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Properties<int>()
.Where(p => p.Name.Equals("Id"))
.Configure(c => c.HasColumnName(c.ClrPropertyInfo.ReflectedType.Name + "Id"));
}
int is the CLR Type of my Primary Key fields. I want to refer to all keys in code as Id but DBA's require keys to be Id with Table entity name prefix. Above gives me exactly what I want in my created database.
Entity Framework 6.x is required.
In Entity Framework 6 Code First:
modelBuilder.Entity<roles>().Property(b => b.id).HasColumnName("role_id");
and update-database...
Change in model
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public long id { get; set; }
to:
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public long role_id { get; set; }
Then remove this:
//modelBuilder.Entity<roles>().Property(b => b.id).HasColumnName("role_id");
A start to the Dynamic approach if NOT using custom conventions
modelBuilder.Entity<Location>().Property(s => s.Id).HasColumnName("LocationId");
You can do this using reflection on the context. Pseudo Code as explanation:
Reflect Context to get a list of POCO names
For each POCO in a dbcontext.
Map Property Id -> string PocoName+Id
Here are the extensions I use for this type of solution.
// DBSet Types is the Generic Types POCO name used for a DBSet
public static List<string> GetModelTypes(this DbContext context) {
var propList = context.GetType().GetProperties();
return GetDbSetTypes(propList);
}
// DBSet Types POCO types as IEnumerable List
public static IEnumerable<Type> GetDbSetPropertyList<T>() where T : DbContext {
return typeof (T).GetProperties().Where(p => p.PropertyType.GetTypeInfo()
.Name.StartsWith("DbSet"))
.Select(propertyInfo => propertyInfo.PropertyType.GetGenericArguments()[0]).ToList();
}
private static List<string> GetDbSetTypes(IEnumerable<PropertyInfo> propList) {
var modelTypeNames = propList.Where(p => p.PropertyType.GetTypeInfo().Name.StartsWith("DbSet"))
.Select(p => p.PropertyType.GenericTypeArguments[0].Name)
.ToList();
return modelTypeNames;
}
private static List<string> GetDbSetNames(IEnumerable<PropertyInfo> propList) {
var modelNames = propList.Where(p => p.PropertyType.GetTypeInfo().Name.StartsWith("DbSet"))
.Select(p => p.Name)
.ToList();
return modelNames;
}
However, you will still need to employee dynamic lambda to finish.
Continue that topic here: Dynamic lambda example with EF scenario
EDIT:
Add link to another question that address the common BAse Config class approach
Abstract domain model base class when using EntityTypeConfiguration<T>
Piggybacking on #Monty0018 's answer but this just need to be updated a little if, like me, you're using Entity Framework 7 and/or SQLite.
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
try
{
_builder = modelBuilder;
var typeName = typeof(T).Name;
_builder
.Entity(typeof(T))
.Property<int>("Id")
.ForSqliteHasColumnName(typeName + "Id");
}
catch (Exception e)
{
throw e;
}
}
This should be a simple one involving EF Code first but I can't wrap my head around the documentation and all the examples I am finding are from older versions. I am working with the latest (4.1).
Anyway I have some models like:
public class Foo
{
public int ID { get; set; }
public Bar Bar { get; set; }
}
public class Bar
{
public int ID { get; set; }
public string Value { get; set; }
}
I used some scaffolding with Asp.Net MVC to create my controllers/repositories and when I create a 'Foo' object, it also creates a 'Bar' object even though I set the 'Bar' property from something stored in the database.
public class FooViewModel
{
public int ID { get; set; }
public int BarID { get; set; }
}
public ActionResult Create(FooViewModel foo)
{
var entity = new Foo()
{
ID = foo.ID,
Bar = _barRepository.Find(foo.BarID)
};
_fooRepository.InsertOrUpdate(entity);
_fooRepository.Save();
// more stuff
}
How can I use fluent syntax for EF in order to stop it from creating a new 'Bar' row in the database?
Update
Here is the generated repository code:
public void InsertOrUpdate(Foo foo)
{
if (foo.ID == default(int)) {
// New entity
context.Foo.Add(foo);
} else {
// Existing entity
context.Foo(foo).State = EntityState.Modified;
}
}
public void Save()
{
context.SaveChanges();
}
your _fooRepository and _barRepository need to share same DB context instance. If the are using two instances the Bar will be in added state.
The problem must be somewhere in your repository layer - using the same model directly with EF 4.1 produces the expected result - a new row in the Foos table with a bar FK column pointing to the existing Bar.