Entity Framework 6 - Knowledge Base (KB)
44 results in tag: many-to-many
Building where clauses to evaluate collections inside a many to many connection using LINQ to entities
So, I am using the Linq entity framework. I have 2 entities: ...Content... and ...Tag.... They are in a many-to-many relationship with one another. ...Content... can have many ...Tags... and ...Tag... can have many ...Contents.... So I am trying to write ...
asked by Phobis
Adding existing entities to a collection on a newly built object using the entity framework
I am using the Entity framework to create a new order. The order contains a collection of contacts, a many to many relationship. I want to add a reference to an existing contact on the order on creation of the order. Both Order and Contact a Entity Obj...
asked by kirkmcpherson
Is Entity Framework and a large number of queries unusable?
I'm trying EF out and I do a lot of filtering based on many to many relationships. For instance I have persons, locations and a personlocation table to link the two. I also have a role and personrole table. ...EDIT: Tables: Person (personid, name) Perso...
asked by John Landheer
How can I destroy a many-to-many relationship in Entity Framework without having to load all of the data?
Does anyone know how to delete many-to-many relationship in ADO.NET Entity Framework without having to load all of the data? In my case I have an entity ...Topic... that has a property ...Subscriptions... and I need to remove a single subscription. The co...
asked by Emil
Many-to-Many Query Problems with Entity Framework - Linq To Entities
I am having problems querying many-to-many relationships in Linq To Entities. I am basically trying to replicate this query using Linq:...Select * FROM Customer LEFT JOIN CustomerInterest ON Customer.CustomerID = CustomerInterest.CustomerID LEFT JOIN In...
asked by JD.
Insert/Update Entity Framework for Many to Many How do I go about doing it?
I'm using EF4 and new to it. I have a many to many in my project and cannot seem to work out how to insert or update. I have build a small project just to see how it should be coded....Suppose I have 3 tables...Class : ClassID-ClassName ...Student : Stude...
asked by user9969
First, create a self-referential many-to-many recursive connection code. Framework for Entities
I can't seem to make this work at all...class Member { public virtual IList<Member> Friends { get; set; } [Key] public int MemberId { get; set; } public string Name{ get; set; } } ...I tried adding Mappings but in vain. Is there a way to d...
asked by Korayem
Many to many Entity Framework code first
I've searched everyhwere but couldn't find an answer......First, I have created a many to many relationship using code first which worked well. Each person can be in multiple clubs and each club can have multiple members. The ...ClubPersons... table has b...
asked by Leon
Create code initially, one by one, with more fields in the association table.
I have this scenario:...public class Member { public int MemberID { get; set; } public string FirstName { get; set; } public string LastName { get; set; } public virtual ICollection<Comment> Comments { get; set; } } public class Comment...
asked by hgdean
Unable to construct a type constant value (type) In this environment, only primitive types ('such as Int32, String, and Guid') are supported.
I've read ALL of:...Unable to create a constant value of type 'System.Object' in Entity Framework...Entity Framework - "Unable to create a constant value of type 'Closure type'..." error...Entity Framework - Union causes "Unable to create a constant value...
asked by Can PoyrazoÄŸlu
Change tracking for many-to-many connections in Entity Framework 4.1+
How can I detect changes of ICollection<> properties (many-to-many relationships)?...public class Company { ... public virtual ICollection<Employee> Employees { get; set; } } using (DataContext context = new DataContext(Properties.Settings.Defau...
asked by Boris Mitchenko
Checkboxes in CRUD Views for Many-Many Relationships
I am having a hard time trying to figure out what I need to do to get this to work. I'm learning ASP.NET MVC CodeFirst with EF. If I make a model I can simply add a controller for that model and add scaffolding to create views that automatically take care...
asked by Shane LeBlanc
Many-to-many mapping table
From examples that I have seen online and in a Programming Entity Framework CodeFirst book, when you have a collection on both classes EF would create a mapping table such as ...MembersRecipes... and the primary key from each class would link to this tabl...
asked by Pricey
MVC + EF Code First Many to Many relationship: Create view with checkbox
I'm a newbie with MVC + EF Code First and have some doubts about many to many relationship. ...I created 2 tables that has many to many relationship (userprofile and courses). Sounds simple but it got pretty complex for me: ...I want to see the "create" ...
asked by PnP
Saving Many to Many relationship data on MVC Create view
I have some issues with a Many-to-many relationship saving the results of a create view....I want to do a create page for a new user profile that has a checklist that lets them choose courses (many to many relationship). My view takes the records from the...
asked by PnP
Build a nested lambda Expression Tree for an Entity Framework Many to Many relationship?
I am trying to build an Entity Framework 4 Many to Many relationship filter, this is for a Dynamic Data project. I know that I need to build an Expression Tree at run time, and I am familiar with doing this for something like a simple where expression li...
asked by Brian Tax
Many to Many Relationships not saving
I have two entities with a fairly standard Many to Many relationship that I created in EF 5 Code First. These are Service and ServiceItem. The Service entity contains a collection of ServiceItems and the ServiceItem contains a collection of Services. I...
asked by drobertson
Entity Framework adding record into many to many mapping table
I have 3 tables, ...1) Customer (Id, Name, bla bla)...2) CustomerGroups (GroupId, GroupName)...3) CustomerInGroups (CustomerId, GroupId)...using (var context = DataObjectFactory.CreateContext()) { context.Customers.Add(entity); con...
asked by Null Reference
Entity Framework Many to Many works but Include does not
I have a typical many-to-many relationship with these 3 tables...[Post] ( [PostId] int, (PK) [Content] nvarchar(max) ... ) [Tag] ( [TagId] int, (PK) [Name] nvarchar ... ) [TagPost] ( [TagId] int, (PK, FK) [PostId] int (PK, FK) ) ...And,...
asked by Ray
MVC 4 - Many-to-Many relation and checkboxes
I'm working with ASP.NET MVC 4 and Entity Framework. In my database, I have a table ...Subscription... which represents a subscription to public transports. This subscription can provide access to several ...public transport companies... (so a subscriptio...
asked by Traffy
