in EF Database First when change ForeignKey(CommodityGroupID) automatic Get CommodityGroup for Commodity object, But in EF Code First(4.3.1) not doing.
public class Commodity
{
public int CommodityID { get; set; }
public string MadeBy { get; set; }
public decimal ServiceTimePrice { get; set; }
public decimal QCPrice { get; set; }
public int ServicePoint { get; set; }
public string Note { get; set; }
public int CommodityGroupID { get; set; }
[ForeignKey("CommodityGroupID")]
public virtual CommodityGroup CommodityGroup { get; set; }
}
public class CommodityGroup
{
public int CommodityGroupID { get; set; }
public string CommodityGroupName { get; set; }
public virtual ICollection<Commodity> Commodities { get; set; }
}
this Property defined in Edmx file (database first), i Should define this code in ef code first?
[BrowsableAttribute(false)]
[DataMemberAttribute()]
public EntityReference<CommodityGroup> CommodityGroupReference
{
get
{
return ((IEntityWithRelationships)this).RelationshipManager.GetRelatedReference<CommodityGroup>("GaamRepairModel.FK_Commodity_CommodityGroup", "CommodityGroup");
}
set
{
if ((value != null))
{
((IEntityWithRelationships)this).RelationshipManager.InitializeRelatedReference<CommodityGroup>("GaamRepairModel.FK_Commodity_CommodityGroup", "CommodityGroup", value);
}
}
}
It sounds like you're wanting a change tracking proxy. You want the CommodityGroup navigation property to update automatically when the FK is changed correct?
See this post on MSDN for details about the change tracking proxy.
This post on MSDN shows some code on how to test of your proxy object is being created properly.
Is this a new object? If so, you'll need to call the CreateObject function on your DbSet, not use the New Commodity().
Related
I am trying to make a simple website that tracks students, programs, and classes. I've created the entities and I'm getting an error when trying to add the migration.
"The entity type 'Program' requires a primary key to be defined."
I have tried using the [Key] attribute and there is an Id field. The other table was created just fine. What else should I try?
Here is the problem class:
public class Program
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public bool UseRanks { get; set; }
}
Here is another table that I had no problems creating a migration for:
public class Person
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string CellPhone { get; set; }
public string HomePhone { get; set; }
public string WorkPhone { get; set; }
public string Address { get; set; }
public string City { get; set; }
public string State { get; set; }
public string ZipCode { get; set; }
public DateTime BirthDate { get; set; }
}
Here is what is in my ApplicationDbContext class:
public class ApplicationDbContext : IdentityDbContext
{
public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
: base(options)
{
}
//public DbSet<Attendance> Attendances { get; set; }
public DbSet<Person> People { get; set; }
public DbSet<Bill> Bills { get; set; }
//public DbSet<Session> Sessions { get; set; }
public DbSet<Program> Programs { get; set; }
}
I've commented out the other entities because I was trying to add them one at a time. Trying to add a migration with all the entities resulted in the same error with the same specific class.
Complete shot in the dark, but based on the name of this class, I'm guessing you're referencing the wrong Program. Make sure that your DbSet<Program> is actually using your Program entity and not something like the Program class used at the console app level. You'll likely need to explicitly use the namespace, i.e. DbSet<MyApp.Models.Program>.
You might also consider changing the name of the class to remove any chance of ambiguity. There's some class names that are just going to wreck havoc trying to use them because they'll conflict with framework stuff constantly. It's usually more hassle than it's worth just to have that particular name. Program is one of those.
You can try to use this way:
public class Program
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public bool UseRanks { get; set; }
}
Adding [Key] attribute to the Id property.
In the file ApplicationDbContext.cs, you can override OnModelCreating method:
public DbSet<Program> Programs { get; set; }
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
builder.Entity<Program>().ToTable("Programs").HasKey(x => x.Id);
}
I have SQLite db and these EF models and context.
Models and Context
public class CardHolder
{
public int CardHolderId { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string PhoneNumber { get; set; }
public string EmailAddress { get; set; }
public string TenantName { get; set; }
public ICollection<AccessCard> AccessCards { get; set; }
}
public class AccessCard
{
public int AccessCardId { get; protected set; }
public CardHolder CardHolder { get; set; }
public DateTime ActivationDate { get; protected set; }
public bool ActivationProcessed { get; set; }
public DateTime? DeactivationDate { get; protected set; }
public string DeactivationReason { get; set; }
public bool DeactivationProcessed { get; set; }
}
public class MyContext : DbContext
{
public DbSet<CardHolder> CardHolders { get; set; }
public DbSet<AccessCard> AccessCards { get; set; }
}
And the Main program
class Program
{
static void Main(string[] args)
{
using (var db = new MyContext())
{
var cardHolders = db.CardHolders.Include("AccessCard").ToList();
}
}
}
Question1: Why do I get this exception
System.InvalidOperationException: 'A specified Include path is not
valid. The EntityType 'SQLiteDemo.Models.CardHolder' does not declare
a navigation property with the name 'AccessCard'.'
If I replace it with
var cardHolders = db.CardHolders.Include("AccessCards").ToList();
I get another error:
SQL logic error no such column: Extent2.CardHolder_CardHolderId
What is wrong with Entity Framework?
Question2: Why cant I use arrow function in Include statement, it doesnt compile at all?
var cardHolders = db.CardHolders.Include(x => x.AccessCards).ToList();
Question3: Why do I need to use Include at all if my ICollection association property AccessCards is NOT virtual - that means eager loading must work by itself!
Why the hell it is so problematic and buggy? Nothing works as it should :(
1 - You have a typo as you have already determined :)
1B - "SQL logic error no such column: Extent2.CardHolder_CardHolderId"
EF isn't finding your FK. You could add it to your AccessCard model:
public int CardHolderId { get; set; }
2 - You need to pull in the LINQ extensions. Make sure you have both of these using statements at the top:
using System.Data.Entity;
using System.Linq;
3 - You, like many others, are misunderstanding lazy loading. Eager loading still requires an Include() to fetch related data. Lazy loading only fetches the relations when you access them.
I am getting this error in my .Net MVC 4 web application:
The property 'Username' cannot be configured as a navigation property. The
property must be a valid entity type and the property should have a non-abstract
getter and setter. For collection properties the type must implement
ICollection<T> where T is a valid entity type.
I am very new to Entity Framework and I can't seem to get around this issue. Here is some code:
//DB Context
public class EFDbContext : DbContext
{
public DbSet<User> Users { get; set; }
public DbSet<Role> Roles { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<User>().HasMany(u => u.Roles).WithMany(r => r.Users).Map(x => x.MapLeftKey("Username").MapRightKey("RoleName").ToTable("Users_Roles"));
}
}
//Entity Classes
public class User
{
[Key]
public string Username { get; set; }
public string Password { get; set; }
public string Email { get; set; }
public string Comment { get; set; }
public int Level { get; set; }
public string PasswordQuestion { get; set; }
public string PasswordAnswer { get; set; }
public bool IsApproved { get; set; }
public DateTime LastActivityDate { get; set; }
public DateTime LastLoginDate { get; set; }
public DateTime LastPasswordChangedDate { get; set; }
public DateTime CreationDate { get; set; }
public bool IsOnLine { get; set; }
public bool IsLockedOut { get; set; }
public DateTime LastLockedOutDate { get; set; }
public int FailedPasswordAttemptCount { get; set; }
public DateTime FailedPasswordAttemptWindowStart { get; set; }
public int FailedPasswordAnswerAttemptCount { get; set; }
public DateTime FailedPasswordAnswerAttemptWindowStart { get; set; }
[InverseProperty("RoleName")]
public virtual ICollection<Role> Roles { get; set; }
public override string ToString()
{
return this.Username;
}
}
public class Role
{
[Key]
public string RoleName { get; set; }
public int Level { get; set; }
[InverseProperty("Username")]
public virtual ICollection<User> Users { get; set; }
public override string ToString()
{
return this.RoleName;
}
}
//Repository
public class EFUsersRepository : IUsersRepository
{
private EFDbContext context = new EFDbContext();
public IQueryable<User> Users
{
get { return context.Users; }
}
public User GetUser(string username)
{
return context.Users.Find(username); //THIS IS WHERE THE CRASH OCCURS
}
}
//DB Setup
Table Users, Role and Users_Role. Users_Role is a simple linking table with [username, role] columns both of type varchar.
The database tables columns & types match the two classes above (User,Role).
I inherited this project which was unfinished but I can't get it to run successfully. Any help understanding what the issue is would be helpful. Thanks!
It might be that Entity Framework is updated. Easiest way will be to recreate the DataModel.
Even if the previous programmer did not use Entity Data Mode, you can at least copy the auto generated code such as EFDbContext, Users and Roles classes.
It turns out, after commenting out enough items all day long, the the following lines are what caused this error for me:
[InverseProperty("RoleName")] //In file User.cs (as shown above)
[InverseProperty("UserName")] //in file Role.cs (as shown above)
I am still learning Entity Framework and I don't know why this was the solution, but it stopped the error which I reported above.
I hope that this helps someone else and if anyone wants to help me understand what the issue was in detail, please feel free. I am eager to learn.
I'm currently building an SPA with Web API and knockout etc. So far i worte my own simple datacontext and it worked pretty well.
The I bumped in to breeze and thought it might be worth a try. especially I hoped to get a simpler approach on navigation between the entities...
to load a entities or a single entity with breeze worked fine. Working with navigation properties seems not to work. The navigation property is always empty, even though it's a one to many relationship.
Here is my model (simplified):
public class WorkdayHours
{
public int Id { get; set; }
public bool IsWorkDay { get; set; }
...
public Byte WeekDay { get; set; }
}
public class Service
{
public int Id { get; set; }
public string DisplayName { get; set; }
public virtual ICollection<WorkdayHours> BookableDays { get; set; }
}
public class Employee
{
public int Id { get; set; }
public string DisplayName { get; set; }
public virtual ICollection<WorkdayHours> BookableDays { get; set; }
}
public class Shop
{
public int Id { get; set; }
public string DisplayName { get; set; }
public virtual ICollection<WorkdayHours> BookableDays { get; set; }
}
Then I fetch the entity service ind my SPA as follow:
var query = EntityQuery
.from('Services')
.where('id', 'eq', serviceId)
.expand('BookableDays');
As when teh query is executed I get as result the requested service entity with all the data except the bookableDay property is always an empty array.
When I check the Json answer I see that also the workdayHours are transmitted and breeze even calls my defined ctors for this entities. However they are not linked to the bookableDays property itself.
When checking the genrated DB model, EF generated foreignkeys for service, employee and shop in workdayHours as expected.
Is breeze not capable with having several optional foreignkeys?
Suggestion and ideas highly apprechiated.
Breeze is dependent on Foreign Keys. I had a similar problem. This should solve it:
EF was generating the ForeignKeys for me too and the related Entites where still empty. As far as i know breeze needs the explicit Annotation/Configuration of ForeignKey Fields.
public class Mvl
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public long MvlId{ get; set; }
public DateTime CreatedAt { get; set; }
[InverseProperty("Mvl")]
public ICollection<MvlOP> MvlOps { get; set; }
public DateTime? ReleasedAt { get; set; }
public DateTime? LockedAt { get; set; }
public DateTime? ClosedAt { get; set; }
//[ConcurrencyCheck]
//public int? RowVersion { get; set; }
[Timestamp]
public byte[] TimeStamp { get; set; }
}
public class MvlOP
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public long MvlOpId { get; set; }
public long MvlId { get; set; }
[ForeignKey("MvlId")]
public Mvl Mvl { get; set; }
...
}
I'm using EF 4.1 Code First, and I'm making a configurable utility for parsing/importing large delimited files. Each row in the file may contain data for several entities.
The exact data and layout for the file will be unknown at build time (it's configured differently for each client), so I'm making it configurable.
Example model (simplified)
public class Contact {
public int Id { get; set;}
public string Name { get; set; }
}
public class Account {
public int Id { get; set; }
public decimal Balance { get; set; }
public bool IsOpen { get; set; }
}
Depending on the client, a file may contain contact info, account info, or both. Because of the size of these files (tons of records), we have to use SqlBulkCopy to do the data loading. It's also unknown at compile time exactly what rules will be run against the data (validation changes by client, etc.)
I want to have a table and class, like ImportRecord, to hold the imported data. My current working class is like:
public class ImportRecord {
public string Contact_Name { get; set; }
public decimal Account_Balance { get; set; }
public bool Account_IsOpen { get; set; }
}
The issue here is that as we add/change fields in the model classes, the ImportRecord has to get changed also -- it's duplicative/less than ideal. It's somewhat important to me that the import data resides in a single table to simplify the SqlBulkCopy import.
My ideal ImportRecord class would look like this:
public class ImportRecord {
public Contact Contact { get; set; }
public Account Account { get; set; }
}
But that would just create a table with two foreign keys (aside from complaining about no FK properties). Is there a way to have the entity classes behave more like a denormalized, keyless, complex type for the ImportRecord? Am I going about this entirely wrong?
Thanks!
Entity cannot be nested and in the same time complex type cannot have entity key so you cannot use one instead of other but you can try this little cheat. I just tested that it at least creates correct database structure:
public class Context : DbContext
{
public DbSet<Account> Accounts { get; set; }
public DbSet<Contact> Contacts { get; set; }
public DbSet<ImportRecord> ImportRecords { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.ComplexType<ContactBase>();
modelBuilder.ComplexType<AccountBase>();
}
}
public class ContactBase
{
public string Name { get; set; }
}
public class AccountBase
{
public decimal Balance { get; set; }
public bool IsOpen { get; set; }
}
public class Contact : ContactBase
{
public int Id { get; set; }
}
public class Account : AccountBase
{
public int Id { get; set; }
}
public class ImportRecord
{
public int Id { get; set; }
public ContactBase Contact { get; set; }
public AccountBase Account { get; set; }
}