I have two DbContext class and some Entities in them. I know this is not good idea to have more than one DbContext but i have to do a lot of works to change my code! so my question is what is the best scenario for add relationship between two Entities with different DbContext?
For example an one to many relationship between User Entity with IdentityDb Context and Comment Entity with SiteDbContext :
public class User : IdentityUser
{
public DateTime JoinDate { get; set; }
public async Task<ClaimsIdentity> GenerateUserIdentityAsync(UserManager<ApplicationUser> manager)
{
var userIdentity = await manager.CreateIdentityAsync(this,DefaultAuthenticationTypes.ApplicationCookie);
return userIdentity;
}
}
public class IdentityDb : IdentityDbContext<ApplicationUser>
{
public IdentityDb() : base("DefaultConnection", throwIfV1Schema: false)
{
}
public static IdentityDb Create()
{
return new IdentityDb();
}
}
public class Comment
{
public int CommentId { get; set; }
[Required]
[StringLength(900)]
public string CommentText { get; set; }
[DataType(DataType.Date)]
public DateTime CommentDate { get; set; }
}
public class SiteDb: DbContext
{
public SiteDb(): base("DefaultConnection")
{
}
public DbSet<Comment> Comments{ get; set; }
}
Short answer: Entity Framework currently doesn't support creating a query which uses more than one context.
For work around: Refer this.
Related
I know my question is kinda broad but I haven't found any good answers online.
I am building an ASP.NET Core MVC web app. I am looking for tips on how to bind a specific user to entities (classes in model). The problem is really about how to bind a certain user to a certain entity in the database.
Any help would be greatly appreciated.
ApplicationUser (or IdentityUser) is like any other entity class.
Creating a 1-n relationship, for example, would look something like:
public class ApplicationUser : IdentityUser
{
public virtual IList<MyEntity> MyEntities { get; set; } // navigation property
}
public class MyEntity
{
public int Id { get; set; }
public string CreatedByUserId { get; set; } // FK
public ApplicationUser CreatedByUser { get; set; } // Navigation property
}
You could also do this the fluent way:
public class ApplicationUser : IdentityUser { }
public class MyEntity
{
public int Id { get; set; }
public string CreatedByUserId { get; set; }
}
public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
protected override void OnModelCreating(ModelBuilder builder)
{
builder.Entity<MyEntity>(b => {
b.HasOne<ApplicationUser>()
.WithMany()
.HasForeignKey(myEntity => myEntity.CreatedByUser);
});
}
}
I'm having problems extending the Fluent API to my inheritance classes. I have taken the TPT (table per type) method and each type of the inheritance has a table. I like table per type because the database is fully normalized and easy to maintain. I am not getting the inherited model ServiceCompany to work with the Fluent API.
Base Abstract Class
public abstract class Vendor
{
[Key]
public int VendorID { get; set; }
[Required]
public string CompanyName { get; set; }
[Required]
public int StreetNumber { get; set; }
[Required]
public string StreetName { get; set; }
}
Inherited ServiceCompany Class from Vendor
[Table("ServiceCompanies")]
public class ServiceCompany : Vendor
{
public string ACHClaim { get; set; }
public virtual ICollection<SubContractorCompany> SubContractorCompanies { get; set; }
public virtual ICollection<ServiceCompanyUser> SubContractorUsers { get; set; }
}
Where I added the entity models to enable the Fluent API with onModelCreating()
public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
public ApplicationDbContext()
: base("DefaultConnection", throwIfV1Schema: false)
{
}
public DbSet<Vendor> Vendors { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<ServiceCompany>().ToTable("ServiceCompanies");
}
public static ApplicationDbContext Create()
{
return new ApplicationDbContext();
}
}
I would like to be able to do something like this with the fluent API.
var ListofServiceCompanies = db.ServiceCompanies.All()
and not like this
var ListofServiceCompanies = db.Vendor.SelectMany( Vendor is a ServiceComapny...etc)
I prefer to set up the entities correctly and make the code nice and easy to use. Any insight or knowledge is appreciated.
You can do that by calling OfType extension method like below:
var ListofServiceCompanies = db.Vendor.OfType<Vendor>().ToList();
Or you can just add a DbSet<ServiceCompany> ServiceCompanies { get; set; } into your DbContext so it will look like this:
public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
public ApplicationDbContext()
: base("DefaultConnection", throwIfV1Schema: false)
{
}
public DbSet<Vendor> Vendors { get; set; }
public DbSet<ServiceCompany> ServiceCompanies { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<ServiceCompany>().ToTable("ServiceCompanies");
}
public static ApplicationDbContext Create()
{
return new ApplicationDbContext();
}
}
Then just call:
var ListofServiceCompanies = db.ServiceCompanies.ToList();
I'm trying to make a relationship between the Users from the table generated by Asp.Net Identity with my own table. The relationship must be many to many, since many Users can work on the same Task (which is my table), and same time an User can work on multiple Tasks.
public class Task
{
public int ID { get; set; }
public string Name { get; set; }
public string UserID { get; set; }
public virtual ICollection<ApplicationUser> Users { get; set; }
}
public class ApplicationUser : IdentityUser
{
public int TaskID { get; set; }
public virtual ICollection<Task> Tasks{ get; set; }
// rest of the code
}
I try it this way but I get an error during migration (or run time)
"One or more validation errors were detected during model generation:"
Please help me solve this problem and archive what I need.
Try it like this:
public class Projects
{
public Projects()
{
ApplicationUser = new HashSet<ApplicationUser>();
}
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<ApplicationUser> ApplicationUser { get; set; }
}
Application User
public class ApplicationUser : IdentityUser
{
public ApplicationUser()
{
Projects = new HashSet<Projects>();
}
public async Task GenerateUserIdentityAsync(UserManager manager)
{
// Note the authenticationType must match the one defined in CookieAuthenticationOptions.AuthenticationType
var userIdentity = await manager.CreateIdentityAsync(this, DefaultAuthenticationTypes.ApplicationCookie);
// Add custom user claims here
return userIdentity;
}
public virtual ICollection <Projects > Projects { get; set; }
}
Application Context :
public class ApplicationDbContext : IdentityDbContext
{
public ApplicationDbContext()
: base("DefaultConnection", throwIfV1Schema: false)
{
}
public virtual DbSet<Projects> Projects { get; set; }
public static ApplicationDbContext Create()
{
return new ApplicationDbContext();
}
}
now when I run this Mvc app and register, the db tables I get is like the following:
and the correct schema:
The things to be questioned are a lot, from my point of view important is to determine if you:
- can/should you mix application context and your model context ?
You can try it as shown below using Fluent API.
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Task>()
.HasMany<ApplicationUser>(s => s.Users)
.WithMany(c => c.Tasks)
.Map(cs =>
{
cs.MapLeftKey("TaskRefId");
cs.MapRightKey("ApplicationUserRefId");
cs.ToTable("TaskApplicationUser");
});
}
Update : you can see this link too.
EntityType 'IdentityUserLogin' has no key defined. Define the key for this EntityType
Error text is not related to your many-to-many relationship. It tips that other built-in entities are not configured properly. So, It would be nice if you provided full definition of your custom DbContext-class and how it is configured.
UPDATE
As i understood u are working with two different contexts. You must work with the same context, cause of u are extending IdentityContext, creating relationships and adding custom types. So problem then will be resolved itself.
Hope, this will help.
I have read and seen few projects that talks about splitting or multiple DbContext and I'm not sure what is the best practice.. should I create each DbContext for each entity or have all entity in one DbContext?
this is what I have for now.
public class PersonsContext : DbContext
{
public PersonsContext() : base("name=EmployeeContext")
{
}
public DbSet<Person> People { get; set; }
}
public class OrderContext : DbContext
{
public OrderContext() : base("name=EmployeeContext")
{
}
public DbSet<Order> People { get; set; }
}
Actually you don't need have to create one DbContext for each Entity. But you can have multiple DbContext for a single database. For an example let's say you want to separate your business aspect and security aspect of the application into two different modules. Then of course you can have two different context such as SecurityContext which has all the entities related to Security and BusinessContext consists of Business related entities.
Ex:
public class SecurityContext : DbContext{
public PersonsContext() : base("name=securitycontext"){
}
public DbSet<User> User { get; set; }
public DbSet<Role> Role { get; set; }
public DbSet<Group> Group { get; set; }
}
public class BusinessContext : DbContext{
public OrderContext() : base("name=businesscontext"){
}
public DbSet<Order> Order { get; set; }
public DbSet<OrderLine> OrderLine { get; set; }
public DbSet<Customer> Customer { get; set; }
}
I am using Entity Framework 6 with Generic Repository and DTOs.
I want to create new entities via navigation property.
Here is my model:
public partial class Project
{
public Project()
{
this.ProjectAssets = new List<ProjectAsset>();
}
public int ProjectID { get; set; }
public string Name { get; set; }
public virtual ICollection<ProjectAsset> ProjectAssets { get; set; }
}
public partial class Asset
{
public Asset()
{
this.Revisions = new List<Revision>();
}
public int AssetID { get; set; }
public string Name { get; set; }
public short Type { get; set; }
public virtual ICollection<Revision> Revisions { get; set; }
}
public partial class ProjectAsset
{
public int MappingID { get; set; }
public int ProjectID { get; set; }
public int AssetID { get; set; }
public virtual Asset Asset { get; set; }
}
I have already created Project. And if i am creating new Asset, then create Project Asset with AssetID from just created Asset, it's OK, but i have to re-fetch Project from DB.
I want to do it in one transaction, like that:
Project.ProjectAssets.Add(new ProjectAsset(new Asset((short)type, fileName)));
ServiceLocator.Default.ResolveType<IPipeLine>().Update(Project);
public void Update<TEntity>(TEntity entity) where TEntity : class
{
var fqen = GetEntityName<TEntity>();
object originalItem;
var key = ((IObjectContextAdapter)DbContext).ObjectContext.CreateEntityKey(fqen, entity);
if (((IObjectContextAdapter)DbContext).ObjectContext.TryGetObjectByKey(key, out originalItem))
((IObjectContextAdapter)DbContext).ObjectContext.ApplyCurrentValues(key.EntitySetName, entity);
//DbContext.Entry(entity).State = EntityState.Modified;
}
But after SaveChanges there is no record in DB, and MappingID still 0.
I thought that ApplyCurrentValues must work with Navigation Properties.
Is there any good way to solve that problem?
EDIT:
I accessing DAL throughBusiness Entities with contain the same properties, but they also implement INotifyPropertyChanged and other WPF stuff. So i think i can subscribe to CollectionChanged event and manualy create/delete entities from navigation property. And in property setters i can call update, but i think it can strongly decrease perfomance.