Entity framework query many to many

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WebApr 10, 2024 · If you perform this query: var studentslist = dbContex.Students.ToList (); Each item on studentslist will have the 'Courses' collection null, because, although the connection/relation exists (between each table), you didn't specify that you wanted that collection populated. For that to happen you can change your query accordingly: var ... WebMar 7, 2012 · 1. I'm trying to better utilize the resources of the Entity Sql in the following scenario: I have a table Book which has a Many-To-Many relationship with the Author table. Each book may have from 0 to N authors. I would like to sort the books by the first author name, ie the first record found in this relationship (or null when no authors are ...

entity framework core - C# .NET 7, I got Nullable Object must …

WebJan 16, 2013 · How do you join two many to many tables in Entity Framework? select * from Users u inner join UserRoles ur on u.UserId = ur.UserId inner join WorkflowRoles wr on wr.RoleId = ur.RoleId inner join Workflow w on wr.WorkflowId = w.Id where u.Id = x. I want to get all the workflows a user is part of based on their roles in one query. WebJul 11, 2024 · entity-framework, + I have 2 classes with joint that has been created by EF5 how can I do a query to get the list of products for specific project in good old days it was simple I just needed to do this. select top(20) p.Id, p.Name from Product p inner join ProjectProduct j on p.Id=j.ProductId and j.ProjectId = ' 1' order by p.Id desc cheapest flat screen tv prices

Entity Framework Core one to many mapping from SQL

WebYou basically do the same for updates. Just fetch the data, modify the graph by adding and removing objects from collections, call SaveChanges. Check this similar question for details. According to your comment, you need to insert a new Class and add two existing Students to it: using (var context = new YourContext ()) { var mathClass= new ... WebDec 2, 2016 · Entity Framework core 2.1 Many To Many Select Query. 0. Entity Framework Core 2.0 Select Query with many-to-many problem. Hot Network Questions Identify a vertical arcade shooter from the very early 1980s Which one of these flaps is used on take off and land? Choosing relational DB for a small virtual server with 1Gb RAM ... WebSep 28, 2012 · 1. I am trying to fetch a collection of entities from a one-to-many relationship as an IQueryable so I can filter the data down before fetching this from the database. To make it clear, consider the following example: I currently have an entity "User" which has a collection of Pictures: public virtual ICollection Pictures { get; set; } cv of a product designer

How do you join two many to many tables in Entity Framework?

c# - In EF Core 5, how can I insert an entity with a many to many ...

WebMay 23, 2013 · 1 Answer. You can and this case must define the many-to-many relationship with Fluent API: modelBuilder.Entity () .HasMany (u => u.StarredWidgets) .WithMany () // <- no parameter here because there is no navigation property .Map (m => { m.MapLeftKey ("UserId"); m.MapRightKey ("WidgetId"); … WebOct 1, 2024 · user has many user profiles, user_profile table join user and profile tables together. (there is a many to many relationship between user and the profile table) user>one-to-many>user_profiles>one-to-one>profiles. user>many user_profiles> one profile. Problem: How can i select user with profile by using linq. sample: cv of a project coordinatorWebСвязь Query many-to-many с linq c#. У меня есть отношение many-to-many между двумя таблицами Game и Role. При маппинге таблиц с Entity Framework таблица которая представляет отношения таблиц не мапилась. cheapest flat screen tv best deals

"WebDec 3, 2024 · Entity Framework Versions: In the year 2008, Microsoft introduced Entity Framework as part of .NET Framework 3.5. Since then, it released many versions of Entity Framework. Currently, there are two latest versions of Entity Framework available one is EF 6 (works with .NET Framework) and another one is EF Core (works with .NET … " - Entity framework query many to many

Entity framework query many to many

c# - Entity Framework Core Multiple Many-to-many with linking …

WebJun 12, 2024 · 22. If you need to filter a Many-to-Many relationship describe below I recomend to use a LinQ Enumerable Any method like this: return result.Where (x => x.Categories.Any (c => c.category == categoryId)); To return a filtered list of entities related by a specific category. EntityFrameworkCore Relationship query example. WebJul 12, 2024 · This is all that entity framework needs to know the many-to-many relation between Posts and Tags. You even don't have to mention the junction table, entity framework will create a standard table for you, and use it whenever needed. ... Many-to-many query in Entity Framework 7. Related. 1137. LINQ query on a DataTable. 857. …

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WebAug 5, 2024 · Now I need a query to get all roles a user has. These roles could be directly associated to a user or inherited from a group, where a group may inherit it from another group. I am new to entity framework core and the only thing I was able to come up with was selecting the direct roles using. var userRoles = context.User.Where(u => u.Id == id ... WebTo query a many-to-many relationship in Entity Framework CodeFirst using LINQ, you can use the navigation properties of the entities involved in the relationship. Assuming you have a many-to-many relationship between Book and Author, where a book can have many authors and an author can have written many books, and the relationship is ...

WebSep 1, 2024 · Language Integrated Query (LINQ) contains many complex operators, which combine multiple data sources or does complex processing. Not all LINQ operators have suitable translations on the server side. Sometimes, a query in one form translates to the server but if written in a different form doesn't translate even if the result is the same. WebEntity Framework 4.1 Code First - Определить связь многие-ко-многим, используя только аннотации данных Можно ли в Entity Framework 4.1 определить отношение …

WebEntity framework knows the many-to-many, it knows that for this a triple join with the junction table is needed, and will perform this triple join. ... Entity Framework Many-To-Many Join Query. 1. Linq to Entities Relationship … WebApr 10, 2024 · var query = from c in dbContext.Customers join a in dbContext.Orders on c.CustomerId equals a.CustomerId into ps from suborder in ps.DefaultIfEmpty() select new { Customer = c, Order = suborder //deal with null, assign some generic object or whatever you need }; var result = await query.ToListAsync(); Console.WriteLine(result);

WebJun 22, 2015 · I have an Item.Item has a Category.. Category has ID, Name, Parent and Children.Parent and Children are of Category too.. When I do a LINQ to Entities query for a specific Item, it doesn't return the related Category, unless I use the Include("Category") method. But it doesn't bring the full category, with its parent and children.

WebYou can update a many-to-many relationship this way (as an example which gives user 3 the role 5): using (var context = new MyObjectContext()) { var user = cont cheapest flats for sale ukWebMay 16, 2009 · You could make this call before the main call and then add the value to your results in a similar manner to above, i.e. PercentageOfArticles = c.Articles.Count () / articleCount. I've added a method to get the Count from the db then applied the result to an extra property of my MenuCategory object. cv of a project managerWebApr 20, 2016 · Many-to-many query in Entity Framework 7. Ask Question Asked 6 years, 11 months ago. Modified 4 years, 1 month ago. ... No Entity Framework provider found for the ADO.NET provider with invariant name 'System.Data.SqlClient' 1. EF7 Core Many to Many Reference object not populated. 0. cheapest flats in indiaWebEntity Framework 4.1 Code First - Определить связь многие-ко-многим, используя только аннотации данных Можно ли в Entity Framework 4.1 определить отношение many-to-many (Code First подход) используя только Data Annotations, без model ... cv of atul cheapest flats in durbanWebFeb 5, 2014 · 1) Create a database view that contains the columns from Contributions plus the fiscal year, import/map that to a new entity and run the queries using that view. 2) Add a computed column into the table and update the model to include that column (make sure you set it as computed in your .edmx or whatever the Code-First uses instead) 4) Create … cheapest flat response headphonesWebMay 18, 2024 · I have two tables that are in "many-to-many" relationship: on the Join table, in addition to the columns that act as foreign keys I also have other columns that I would like to map in EF Core. The only solution I can think of is to create the relationship as it was done in EF Core 3, that is to use a "one to many" relationship with the join table. cv of a school leaver