2024 Entity framework query many to many

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 ... 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; }

getting array of ID fields in many to many relationship in Entity framework

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. WebNov 3, 2024 · Entity Framework is an Object-to-Relational Mapper, Mapper being the key term here. ... If the database does not support recording a mapping between students and their courses where you can query how one student can participate in many courses, while each course can have many students participating, then EF cannot be configured to … bury saint edmunds golf club

EF Core many-to-many fetch query - Stack Overflow

WebEntity Framework 4.1 Code First - Определить связь многие-ко-многим, используя только аннотации данных Можно ли в Entity Framework 4.1 определить отношение … 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 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 ... hamstick beam antenna

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WebFeb 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 … WebNov 24, 2024 · Either manually configure the relationship, or ignore this property using the ‘ [NotMapped]’ attribute or by using ‘EntityTypeBuilder.Ignore’ in ‘OnModelCreating’. First thing we need to … hamstick dipole tuningWebApr 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. ham stick base

"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. … " - Entity framework query many to many

Entity framework query many to many

Many-to-many relationships without link tables/models?

WebJun 25, 2015 · Using Fluent API I created a many-to-many relationship between Store and StockGroup as well as StockItem and StockGroup. This in turn creates two join tables. The issue I am having is I cannot seem to create a query that spans from Store to StockItem or the reverse without using foreach loops. For example: Given a single StockItem, I would … 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 ...

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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 ... Webcase when exists (query) cast 1 bit case when Not exists (query) cast 0 bit which indicates that the query is run twice when it shouldn't have to. I'm trying to find a way to do with without querying twice.

WebJan 11, 2024 · Since you don't want to query the database, then you can opt to Attach tag instances that you can guarantee are legal tag rows. If you have a reasonable # of Tag IDs to use you could create and attach the full set to reference. ... Many to many relationship entity framework core db first. 186.Net Core 3.0 possible object cycle was detected ... WebFeb 25, 2024 · Entity Framework will create Books, Categories and also the joining table CategoryBooks in the database. The CategoryBooks table will include the PK (Primary Key) of both tables Book_BookId & …

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. WebMay 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.

WebThe Entity Data Model (EDM) abstracts the logical or the relational schema and exposes the conceptual schema of the data using a three-layered approach i.e. The Conceptual Model (C- Space), Mapping model (C-S …

ham stick groundingWebvar cat_id=1; // Change this variable for your real cat_id var query= from article in db.Articles where article.Categories.Any (c=>c.Category_ID==cat_id) select article; This way you will get the articles that satisfies the condition you want. This is the sql code that is … ham stew slow cookerWebMay 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"); … hamstick manualWebSep 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. hamstick impedenceWebYou 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 ... bury salt teamWebYou 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 ham stick mag mountWebEntity 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 … bury saint to sell house