ef core update child collection

Saving Related Data - EF Core | Microsoft Docs Tracking data changes with Entity Framework Core History/Audit of data changes using Entity Framework Core. Because the model that gets posted to the WebApi controller is detached from any entity-framework (EF) context, the only option is to load the object graph (parent including its children) from the database and compare which children have been added, deleted or updated. EF Core has a few new features that allows a DDD approach to building classes that EF Core maps to a database (referred to as entity classes from now on). November 10th, 2020. Specifically . I wrote an article called Updating many to many relationships in entity framework back on 2014 which is still proving to be popular in 2017. There are a number of benefits to using a DDD-styled entity classes, but the main one is that the DDD design moves the create/update code inside the entity class, which . Behaviors that maps to the database & those who do not. Entity Framework Extensions UpdateMatched AndCondition Expression . One-to-Many Relationship Conventions in Entity Framework Core In the previous chapter, you learned about the EF conventions which map entities to different objects of the database. With this post I'd like to spell out different ways of doing it. EF Core API builds and execute UPDATE statement in the database for the entities whose EntityState is Modified. The common tree… It just takes some time to get the first non-relational providers. is: yes. Steps to reproduce Given is a DbContext with 2 entities Product and ProductGroup. Get monthly updates by subscribing to our newsletter. Entity Framework defaults to lazy loading and allows you to override it when necessary. Make changes on entity's properties. Run the app, select the Courses tab, click Create New, and enter data for a new course: Click Create. public class Entity : IEntity { [Key] public int Id { get; set; } } public abstract class RecursiveEntity<TEntity> : Entity, IRecursiveEntity<TEntity> where TEntity . This is a general availability/release to manufacturing (GA/RTM) release that addresses final bugs identified in the previous release candidates and is ready for production. Note: You cannot mix Include & IncludeFilter. ajcvickers added a commit that referenced this issue on Feb 1, 2018. EF Core 5.0 is released simultaneously with .NET 5.0. In this blog post we will check a few LINQ queries and see which of them are executing N+1 SQL statements where N is the number of selected records. Learn Entity Framework update-matched-and-condition-expression by example. One reason is that using Collection is compatible with EF Core 1.1 and using Reference is not. Then you need to run the standard Add-Migration and Update-Database commands to update your database to add the new field. The only thing is: you don't do it out of the box. While EF Core doesn't offer a `Copy` method, there are simple ways to duplicate an entry in a database. The other reason I switched is that this code gives me access to the EF DbCollectionEntry object which is a change worth making: I can use DbCollection to speed up my application whenever I use . UPDATE 2017: I have written a new version of this article for Entity Framework Core (EF Core) to celebrate the release of my book Entity Framework Core in Action. Sometimes it's just cool to take a walk through some technology to find all the different ways you can solve a problem -- sort of "Fun with the .NET Framework." Here's a look at all the ways that Peter could think of to update an object in a collection . Entity Framework AddOrUpdate. The "out of the box" way to update any entity, whether it be a parent or a child in some collection is: Fetch entities from the database. There are two scenarios to save an entity data: connected and . So here is the updated controller action with null and safety checks omitted: public async Task<OutputDto> Update (InputDto input) { // First get a real entity by Id from the . Tracing data changes can be beneficial in narrowing down the issue that may occur in production. Is it really impossible to update child collection in EF out of the box (aka non-hacky way)? . One of the very common questions I am getting from .NET community is how to configure and use the tree structures in EF Core.This story is one of the possible ways to do it. I don't see this being any different if you are using EF Core or not. ; ClientCascade: Delete the Child Records both in the client only. EF Core does NOT work the same way as EF6.x and the new article provides information on how to handle many-to-many relationships in EF Core. To use lazy-loading, the simple way is to install the Microsoft.EntityFrameworkCore.Proxies and enable it by calling UseLazyLoadingProxies () in OnConfiguring method on your data context. Add the dependent to the principal's collection property Our first thought might be something like: This post gives a brief overview of the different approaches. In lazy loading, the related data is transparently loaded from the database when the navigation property is accessed. Using Entity Framework Core this would be configured like this: So let's say we wish to produce a q uery to return a list of of the root most categories such that they also contain any child categories and in turn these child categories contain their subcategories and so on. EF Core provides a variety of ways to start tracking entities or change their state. You learned about the Conventions for One-to-Many Relationship.Generally, you don't need to configure one-to-many relationships because EF Core includes enough conventions which will automatically configure them. You would have to get the parent with child collection in context, which would be read it before you could update the parent, update a child in the collection or add a child . EF Core will enable lazy-loading for any . The procedure is the same as we did it for the create actions. Entity Framework Core: Saving Data in Connected Scenario. Change tracking. A brief bit of background. Try it in EF6 | Try it in EF Core. This first section explores a number of ways in which relationships can be created between an existing principal entity and newly created dependents. One of the very common questions I am getting from .NET community is how to configure and use the tree structures in EF Core. Without it there is no way to generate a consistent graph when there are cycle since each instance would be materialized differently in results. 16. If you don't want EF Core change tracker operation to process the related data, set the EntityEntry.State rather than calling DbContext / DbSet methods like Attach, Add, Update, Remove etc.. (Unless you would track the changes with your own tracking . Learn how an entity framework update records to the database. Delete behaviors. A common pattern for some applications is to either add an entity as new (resulting in a database insert) or attach an entity as existing and mark it as modified (resulting in a database update) depending on the value of the primary key. I am hooking into the SaveChanges event to do the check. I have shown this in the below image. Creating relationships. The department name in the Index page list comes from the navigation property, showing that the relationship was established correctly. Deleting an entity is done using the Remove or RemoveRange method of the DbSet.Alternatively, you can also set the entity state as Deleted.We can delete records either in connected or disconnected Scenarios. We can update records either in connected or disconnected scenarios. Here, you will learn about the behaviours of different methods on the root entity and child entities of the disconnected entity graph in Entity Framework Core. Here, you will learn about the relationship conventions between two entity classes that result in one-to-many relationships between corresponding tables in the database. Here is a way to achieve this: Define a mapping Product -> ProductViewModel used to flatten the members of Product. HINT: A lot of factors might affect the benchmark time such as index, column type, latency, throttling, etc. This issue presents itself when you are dealing with disconnected/detached Entity Framework POCO objects,. Entity Framework knows your one-to-many and understands that your use of the ICollection should result in an inner join followed by a Group By. Working With Entity Framework Detached Objects. The first thing to note is that your proposed query can't be evaluated fully as SQL because there's no SQL equivalent for a collection containing non-primitive values, tagSearchValues.This causes EF to auto-switch to client-side evaluation.That is, it pulls into memory all entities that meet the stuffFilter condition and all of their tags, and then it applies the tags predicate. What you are asking is quite simple in EF Core. TIP: When we write only read-only queries in Entity Framework Core (the result of the query won't be used for any additional database modification), we should . Save changes. In the disconnected scenario such as in a web application, the . This story is one of the possible way to do it. Also how is a parent going to be an object in the child? Entity Framework Core supports various database management systems . If I add a child entity with the PK set, EF marks the added child entity as detached instead of added. Accepted Answer. EF Core 1.1 Add, Attach, Update, and Remove methods. In the connected scenario, the DbContext keeps track of all entities so it knows which are modified and hence automatically sets EntityState to Modified.. I think what you meant is having 3 models - persistance model (one that ef core maps to), - domain model , - dto model which is obvioussly overcomplicating things imo. Throw when attempting to lazy-load after no-tracking query. So I wrote a Get-method that does it for me:. By default, for required relationships, a cascade delete behavior is . Complete Insert/Update/Delete of Child Entities in Entity Framework. is: yes. 4. If you want to filter the related data before loading then use the Query() method. In EF Core 2.2.x this behavior worked, however it no longer seems to work in EF Core 3.0. We can attach a relational entity to the main entity, modify it and EF Core will do the rest for us as soon as we call the SaveChanges method. Update () method in DbContext: Begins tracking the given entity in the Modified state such that it will be updated in the database when SaveChanges () is . It can have one out of the 5 different values, these are 'Added', 'Deleted', 'Detached', 'Modified' & 'Unchanged'. To update an entity with Entity Framework Core, this is the logical process: Create instance for DbContext class. This can be achieved in several ways: setting the EntityState for the entity explicitly; using the DbContext.Update method (which is new in EF Core); using the DbContext.Attach method and then "walking the object graph" to set the state of individual properties within the graph explicitly. The Courses Index page is displayed with the new course added to the list. However, database schemas often use Duplicating Related Entities using Entity Framework Core Add, Attach, Update, and Remove methods in EF Core 1.1 The Department Model is the Principal entity (or parent) as Employee entity needs it. Inside the root directory of our application let us create a new folder called Core, inside the core folder will create another folder called IRepositories. Summarized: if you think you'll need a join in entity framework, think twice, you'll probably be able to do it simpler by using the ICollection or the reference to the parent. some of which may be foolish. This is especially relevant for insert and update scenarios, where we sometimes need to work with thousands of objects. If you need to change the primary key of a related entity, you need to first remove that related entity from the relation and just add a new one with an updated key. EF Core Tips Don't call Update when you don't need to! VERSION WARNING (EF Core 2.0.0): At the time of writing nested collection projections only work in memory, defeating the purpose of using them in the first place. In EF 6 this scenario threw exception. If you are using EF core 2 for SQL Server, and you remove an entity from a child collection in a Parent,, EF sets the state of the deleted entity to be Modified, but it does delete the entity from the DB when you call SaveChanges. December 23, 2013. I see all kinds of code while investigating issues and answering questions on GitHub. Working with Disconnected Entity Graph in Entity Framework Core. Define a mapping Category to CategoryViewModel. That is, I think, a good thing -- but not enough of a good thing to qualify as the "best." Fundamentally, lazy loading means that the child objects at the end of a navigation property aren't retrieved unless you explicitly work with the navigation property . . Try it: EF Core | EF6. Each DbContext instance tracks changes made to entities. This will be fixed soon, so it's still worth understanding. EntityState is an enumeration that stores the state of the entity. When mapping a collection property, if the source value is null AutoMapper will map the destination field to an empty collection rather than setting the destination value to null. With tools like Entity LINQ we can easily write efficient data modification queries. EF Core executes Insert Operation for the entities whose EntityState is set to 'Added'. As an example, here's some code that accepts an object holding updated Customer . 951e6b2. The BeginCollectionItem method is a custom HTML helper method which sets a renders a hidden input with the row's index so that the ASP.NET MVC model binder correctly generates the collection after submitting the form. Adding relationships to the update operations in EF Core is pretty easy. This is what I feel, that its a version issue, this works fine in ef 6 as you have mentioned, but not in EF 4.2, due to which I am facing the issue of Multiple primary key. Tracking queries. It makes no sense and could be a possible circular reference. Scenarios. The above code updates the Department name of the department with Id 1.It set's its name to Designing.. It tracks changes in properties and associations of all entities that are attached to a context. Is it possible to update child collection in EF out of the box. I have a simple entity which owns many children. It will contain the primary/alternate key properties, which will be inserted into the Depdendent . Those who do not map to the database starts with the prefix Client.. Cascade: Delete the Child Records both in client & Database. The Entity Framework Core defines two sets of delete behaviors. You can remove a relationship by setting a reference navigation to null, or removing the related entity from a collection navigation. Entity Framework Core (EF Core) change tracking works best when the same DbContext instance is used to both query for entities and update them by calling SaveChanges.This is because EF Core automatically tracks the state of . After the database update is completed, we can check our sqlite db with the SQLite browser, we can see that the table has been created for us. It all depends on the volume, where, how long and how do you want to query actions . This is the typical way to update an entity in the database . I then remove all the children and add a new child and also update one property on the parent entity. It will update all the records except for the last one because the CreatedDate property is updated. In the below scenario I first fetch an entity along with a related child collection. And I can't upgrade it due to the application being in maintenance mode. Removing from a collection navigation Removing a dependent/child entity from the collection navigation of the principal/parent causes severing of the relationship to that principal/parent. The " .Where (s => s.Age > 25) " is a second part of the query where we use a LINQ command to select only required rows. In EF Core 2.2 while it worked upto an extent, it was not always accurate either (subject to garbage collection else you would get inconsistent results there too). For EF Core 5.0, we have made the model view easier to read and added a new debug view for tracked entities in the state manager. The common tree structures are file tree, categories hierarchy, and so on. Microsoft now has the first preview for an EF Core provider for Cosmos DB. Modify their properties or add/remove elements to their collections; Call . Assuming you're using the latest version of Entity Framework, the easiest way to update your database is to use DbContext's Entry class: It's just two lines of code no matter how many properties your object has. Whenever you access to a property/collection, EF Core automatically performs an additional query to load the property/collection from the database. Principal Entity. I've been wanting to play around with the Cosmos DB provider for a while, so when EF Core 3 was released I decided its time to take . Updating Entity Framework Objects with Changed Data. Best Entity Framework Core Books The Best EF Core Books, which helps you to get started with EF Core . The code - await context.Entry(emp).Reference(s => s.Department).LoadAsync() loads the related entity called Department of the Employee entity. With this I have to do my first experiments using… To celebrate the release of my book Entity Framework Core in Action I am producing an updated version of that article, but for Entity Framework Core (EF Core).. All the information and the code comes from Chapter 2 of my book. The only parameter of the helper method is the collection property name from the master form's view model which we will implemented next. 5. Also noticed the foreign key constraint in the child. This aligns with the behavior of Entity Framework and Framework Design Guidelines that believe C# references, arrays, lists, collections, dictionaries and . EF will automatically populate the parent ID to all child objects I n the collection. In Entity Framework Core we can have recursive entities. Sending those objects to the database one by one is usually significantly slower than in a batch. EF Core sees that the post has been added to a new blog and automatically removes it from the collection on the first blog. Part of #10042, #10509, #3797 It would be good to make this work in a future release, but this involves running a no-tracking query with fixup where the root entity is already materialized. Owned entities are essentially a part of the owner and cannot exist without it, they are conceptually similar to aggregates.This means that the owned entity is by . Updating Relationships in EF Core. This might not be something that you worry about. Entity Framework Core provides different ways to add, update, or delete data in the underlying database. TL;DR - summary. Notice how the id names used between the two entities match up. If you are using Entity Framework Core you have several ways to store actions performed against your data. The child has a ParentId that matches ParentId in its parent. These tracked entities in turn drive the changes to the database when SaveChanges is called.. Update Record in Entity Framework. Fastest Entity Framework Extensions . In this article. The key here is that I'm using conventions to tell EF that there is a parent-child relations. The BulkUpdate method is fast but also flexible to let you handle various scenarios in Entity Framework such as:. Entity Framework Core (EF Core) was designed to not being a framework for only relational databases. I have a Repository using EF Core. An entity contains data in its scalar property will be either inserted or updated or deleted based on its EntityState . 10 min read. And because EF Core allows mapping to backing fields it seems like I can even avoid [JsonIgnore] and just use backing field to get DependentEntity with IsActive=1 from my collection. Learn how to delete records from the database using Entity Framework Core. 8. Is it possible to update child collection in EF out of the box. In the previous chapter, you learned how the ChangeTracker automatically changes the EntityState of each entity in the connected scenario. Finally, we have ToList () method which executes this query. With Entity Framework Core (EF Core) the SQL statement generation has changed - in some cases for the better, in others for the worse. Now we need to start by creating our repositories. In the Disconnected scenario, we already have the entity with use. Jeremy. Configure One-to-Many Relationships using Fluent API in Entity Framework Core. Entity Framework Core offers a number of approaches to the creation and modification of one-to-many relationships. The Reference property gets the reference of related data and the LoadAsync() method loads it explicitly. In the connected Scenario, we open the context, query for the entity, edit it, and call the SaveChanges method. ; SetNull: Set Foreign Key as NULL in both in Client & Database. ASP.NET Core 5.01 (Blazor/Wasm, Kestrel Hosted) Entity Framework Core 5.01 / SQLite Visual Studio v16.9.0 Preview 2.0 I'm trying to configure a many-to-many relationship in my (Shared Folder) protobuf file with the video.proto code sampl. The Problem Defined. Now is the time. Notes: PromatCon: the entity object; amList: is the child list that you want to add or modify Part 2 - Azure CosmosDB with .NET Core EF Core When I first found out EntityFramework supported Azure CosmosDB, I was honestly pretty excited. Not because I thought it would be revolutionary, but because if there was a way to get new developers using Cosmos by leveraging what they already know (Entity Framework), then that would actually be a . The Principal Entity can exist on its own. For example, when using database generated integer primary keys . If you want to add a new entity (record) then it's . Debug views are an easy way to look at the internals of EF Core when debugging issues. First, this is my RecursiveEntity<T> base-class:. Maybe you need to instance the child collection in the parent before you add a child to the collection. A debug view for the Model was implemented some time ago. In this article I am showing how to configure it to handle entity's child collections that those properly gets added and removed from collection. One thing that frequently crops up is calling DbContext.Update or DbSet.Update when it is not needed. The reason why EF Core does the update here is because the entity has a valid property key value (which is '1' in this case). AddOrUpdate. If you are just adding a new child to the parent collection, the you set the object's state to 'add'. Updating related data with Entity Framework Core. Update and include/exclude properties The best way to avoid this being an issue is to use a short-lived context for each unit-of-work such that the context starts empty, has entities attached to it, saves those entities, and then the context is disposed and discarded. Of course EF tracks changes in navigation properties. Queries will automatically track returned entities unless tracking has been turned off. Update Data in Disconnected Scenario in Entity Framework Core. The only thing is: you don't do it out of the box. Define a mapping ProductWithCategories -> ProductViewModel that maps the categories, and then in the aftermap, map the Product: as the DbContext doesn't track changes to entities. But we cannot do an "Include" for these recursives (can we?). I created the tables using the entity framework tooling. This behavior is different from EF6 where methods and setting state are doing one and the same, and is partially mentioned in the Saving Related Data . Handling child collections in Entity Framework. Retrieve entity by key. Use this generic sub to mark the child state, easy to use. Removing a relationship can have side effects on the dependent entity, according to the cascade delete behavior configured in the relationship.