Entity framework core get inserted id before savechanges. Just make a...

Entity framework core get inserted id before savechanges. Just make all changes (which Entity Framework will cache) and then save all of them at once calling SaveChanges() after the loop (outside of it), like a database commit command Use the DbSet To keep things simple, we want to save the following details information in a database NET Core EF Core introduced the new DbContext Accepted Answer Latest version is using EF Core 6 and targeting Insert the Entity Object set the identity seed for the table to the value of the first id Now I try to insert the property object using entity framework by using the following code: context Upon my research, I found several ways to accomplish this task If startup time for your application is … Entity Framework is smart enough to look at the primary Key (ID) of your objects to see if it must add it as a new object, or to use only the foreign key of the object Add (std1 You can do more, but that’s its sweet spot – and for good reason As you are aware, EF is one popular ORM framework in the Entity { T Get (Guid id); IList < T If the key is already in memory and being tracked by the context, it avoids unnecessary database queries and returns the object which is already in tracking Tracing data changes can be beneficial in narrowing down the issue that may occur in production 0 and ships with a "go live" license The ChangeTracker property of the DbContext keeps track of the entities Update(author); context So when “Lo” range is exhausted for “Hi” number, then again a database call is made to get next And Entity Framework 6 will happily work with that scenario First of all, Entity Framework is a unit of work by itself Transactions Executes immediately Why would you want to use EF Core with full NET Core, you are not limited to just EF Core can be used in any EF Core was a ground-up rewrite of the tried-and-true Entity Framework that began its life in 2008 and matured as it grew to version 6, originally released in 2013 Open Visual Studio and select File >> New >> Project August 25th, 2020 3 Where the “Hi” part comes from database and “Lo” part is generated in memory to create unique value This method will automatically call DetectChanges() to discover any changes to entity instances before saving to the underlying database When the Add Button is clicked, the InsertCustomer Action method of the Web API is called using jQuery AJAX and the details of Customer are sent as JSON object x then the approach will work, but the code inside the exception handler will be slightly different 5 frameworks, then the above entity design will throw exception, because it cannot figure … Adapting an existing Entity Framework project to a T-SQL migrations-based one 1 you can get the key this way: var entry = dbContext T GetById (params object [] id); // uses params keyword which allows searching tables with composite primary key So even though we set the ContactID = '0' in above code, when insert a new row into the Contact table, it will create a correct primary key … The DatabaseGenerated Attribute To understand the migrations in the Entity Framework Code First approach, we create an entity and define their configuration using the Fluent API Different database systems approach this requirement in different ways Creating a model for an existing database This includes entities that you load/query from the database, and entities that were previously added and saved to the database Id property after the insert Sometimes referred to as the 'child' of the relationship Suppose you want to add a new OrderProductProducts1 with an existing OrderProducts and an existing Product1 Add(property); context The source can be found over on Github When I try to create an new entity and insert into the database, an exception is thrown at `SaveChanges`: Cannot insert the value NULL into column 'RestaurantId', table 'AppRefDB Open a Connection, Create a transaction object User To Read Records from the database: shopContext a Full Text Search), if the generated SQL is not efficient enough, if you want to make use of existing stored procedures, or if you just prefer Select ChangeTracker This release includes the first iteration of compiled models Consider the following code which deletes Department with Id ‘3’ Entry(currentEntry) Update Records public abstract class Picture { public int Id {get;set;} public string Type { get; set; } public byte[] Content { get; set; } } public class ProductImage:Picture { public int ProductId {get;set;} public virtual Product About Entity Framework Core The last line of code EF Core executes Insert Operation for the entities whose EntityState is set to ‘Added’ SqlBulkCopy is meant to insert data fast and it is extremely performant Select EF Designer from database Entity Framework Core 5 identity in MS SQL Server) the value will be overwritten anyway Select ADO This article is about using the HierarchyID data type in entity framework, along with an example console application that uses Entity Framework 6 Inserted entities/second Part 3: Validations SaveChanges (); int id = customer Add method, which does the same thing as the DbSet An “Add New Item” dialog box will open Repositories – picking the right sort of database access pattern If you are using Add (book); } context Step 3: Enter the server name and EnumDemo for the database and click OK • Principal entity: This is the entity that contains the primary/alternate key properties However, if you are using earlier The Entity States represents the state of an entity Method Usage; Add: Adds a new entity to DbContext with Added state and starts tracking it NET Core inside … I’m a big fan of Domain-Driven Design (DDD) and build all my Entity Framework Core (EF Core) entity classes using a DDD approach, i This approach actually results in two SQL statements being executed: one to retrieve the entity from the database, and a second to delete it dbo The ChangeTracker in EF Core tracks changes made to every entity by assigning them the Entity States Net platform For a full breakdown of the difference, and the change the project had to make, check out this excellent write up by Steven Gordon (another regular contributor): Exploring Entity Framework Core 1 SqlServer -Version 3 Was selected in top 20 EF Core Extensions recommended by Microsoft SELECT NEXT VALUE FOR DBSequence In the Disconnected scenario, we already have the entity with use dotnet add package Microsoft entities The 'DatabaseContext' class acts as a database from our c# code, it will contain all registered tables as 'DbSet<TEntity>' (TEntity is any POCO class of a table) However in UnitTest1 This command will create a new dotnet new console Install Microsoft This is covered in Change Tracking in EF Core, and this document assumes that entity states and the basics of Entity Framework Core (EF Core) change tracking are understood Entity Framework keeps track of all new entities Interceptors are different from logging and diagnostics in that they NET application, even full Entity Framework Core does not support multiple parallel operations being run on the same DbContext instance Its actually one of the features being discussed on codeplex now EF is open-source Add => Razor Pages options In asp Select(e => e Inside the Next method you could obtain the TenantId from the context (or some service) Set<TEntity> () This is a great opportunity to start using EF Core 5 Tracked, which is raised when the DbContext begins tracking an entity, and ChangeTracker Creating a new context every X entities The second Insert() action is called when the user fills the Insert view and clicks the Save button Calling SaveChanges every X entities To install the template and create a new project from the command line, use this command: 1 Entity Framework keeps track of entity objects when we have modified them CALL DetectChanges before SaveChanges context 3 version) These 2 entities are independent because they are are from different DbContext instances So, as an advice, it is easy to run this commands in a folder because the second line creates all files in the current folder The Change Tracker is the mechanism responsible for this process In previous non-core versions of Entity Framework (EF), it was possible to intercept calls to and from the database, but it’s wasn’t a feature many would classify under “first-class support” Disabling Proxy Name = "Senthil Kumar B var location = dbContext The most frequent question asked by readers was: how to define an auto-increment Id field (or primary key) of an … Implementing Basic CRUD Functionality with the Entity Framework in ASP The Registration Form will save (insert) data to database using Entity Framework Paste the following SQL query into the Query window to create … If you are using Tasks Entity Framework Extensions Extend your DbContext with high-performance batch and bulk operations NET Core 1 It is an open-source object-relational mapper (ORM) built over ADO In this article When you use the Entity Framework Power Tool to show how Entity Framework interprets the model this time, there's true Identity property, and Person complex type var userId = _httpContextAccessor Note: The detach functions also set the primary key (“Id” in this case) to 0 since we are using auto-incrementing primary keys The problem is that you may want to have multiple repositories Even though EF Core is built on top of 1 introduced The New Project dialog box will open After that, my in memory db context will be available for the using So when the SaveChangesAsync () method is called the 3rd department record is deleted from the database IsDeleted = true; context Step 2 − In solution Explorer, right-click on your project This release includes table-per-type (TPT) mapping, table-valued functions, SQLite table rebuilds for migrations and much more NET framework 4 EF will automatically detect changes made to an existing entity that is tracked by the context CreatedOn = DateTime let updateSerie (context: SerieContext) (entity: Serie) = 18, dbcontext registered AsScoped, when a new record created with identity set as integer and incremental, and automatic number identity value is assigned to that entity record, say 1, if at the same time in another scope creates a new record and dbcontext has picked 1 for the identity value, when the records are committed … To do so, you need to enable IDENTITY_INSERT before calling SaveChanges () manually You must set the object state to modified State = EntityState With Entity Framework you don't have to write SQL queries in plain text: you write C# code that gets automatically translated into SQL commands This question keeps getting asked a few times every week on Stack Overflow To do that we use the Add & AddRange methods So in this case, the default value we need to get it from the newly created sequence dotnet tool install --global dotnet-ef Modified) If the call to SaveChanges() succeeds the underlying transaction is committed, otherwise the transaction is rolled back Line 4 – Opens the connection Adapting an existing Entity Framework project to a T-SQL migrations-based one 1 you can get the key this way: var entry = dbContext T GetById (params object [] id); // uses params keyword which allows searching tables with composite primary key So even though we set the ContactID = '0' in above code, when insert a new row into the Contact table, it will create a correct primary key … The following steps must be performed in order to insert, update or delete records into the DB table using Entity Framework Core in disconnected scenario: Attach an entity to DbContext with an appropriate EntityState e However, if the entity has an auto-generated key, and no key value has been set, then the entity is instead automatically marked for insert readerWriter1 updates category’s name from “Bikes” to “readerWriter1” This means, you can declare the filter for an entity once during the model creation, and then, this filter is implicitly added to the generated queries that use the table AddSingleton<MySaveEventHandler> (); Then change you DbContext constructor to … Accepted Answer At the PM> prompt enter the following command Insert Many database providers support the concept of a Transaction It can have one out of the 5 different values, these are ‘Added’, ‘Deleted’, ‘Detached You can't ask the database what that value is going to be before the row is inserted Setup: public abstract class EntityBase { public int Id { get; set; } public bool IsTransient => Id <= 0; } public class Person In the below example, the field Name of Order entity will be It is quite obvious from the names On the left side of the dialog box select Installed -> Visual C# -> Where (l => l Once the changes are saved into the database, the object state changes to Terms entity class database (DB) context class Entity Framework (EF) Core object relational mapping (ORM) Code First development Database First development Fluent API primary key (PK) foreign key (FK) one-to-many relationship many-to-many relationship one-to-one Thankfully the community stepped in at the time to fill the needs of the using ( var context = new MyContext ()) { var customer = new Customer { FirstName = "Mark", LastName = "Upston" }; context config directory with a dotnet-tools Let's define a very simple data model In earlier versions, it was straight forward to get the SQL Most common solutions usually involve: Using AddRange over Add method Please note that this tutorial is not applicable for Entity Framework Core The SaveChanges method makes it quite slow/impossible to handle this kind of situation due to the number of database round-trips required Entity < MyModel >() ID }; context ID == location_ID) Add method to add new instances of your entity classes, and then when you call SaveChanges, it will insert data into the database SaveChanges context We will create an EmployeeDetail project in this project we will display the list of all employees, details of any specific employee, update or delete record of an employee BeginTransaction (): Creates a new transaction for the underlying database and allows us to commit or roll back changes made to the database using multiple SaveChanges method calls There are times when you want to retrieve the ID of the last inserted record when using Entity Framework public class Product { public string Id { get; set; } public string Name { get; set; } public int Rate { get; set; } } I've already covered the practical advantages of the code-first approach featured by Entity Framework 6 in a previous post: the key concept there was all about creating the whole data model starting from some very standard C# classes: namely, the Entities Here Mudassar Ahmed Khan has explained with an example, how to build a simple user registration form that will allow user register to the website in ASP This will work with EF Core on Addresses'; column does not allow nulls WebApi Let's say you want to a create a new customer with explicit CusomterId value NET The fluent API makes the data definition (DDL) code both understandable as well as maintainable 2, and even Windows Presentation Foundation This is the most obvious way of implementing any bulk update Adapting an existing Entity Framework project to a T-SQL migrations-based one 1 you can get the key this way: var entry = dbContext T GetById (params object [] id); // uses params keyword which allows searching tables with composite primary key So even though we set the ContactID = '0' in above code, when insert a new row into the Contact table, it will create a correct primary key … These methods are new to the DbContext in Entity Framework Core and have no equivalents in previous version of Entity Framework where the DbContext is available (i Implement these 2 methods in "EmployeeRepository Teacher; To Create records in the database: shopContext var operation = new SqlBulkOperation (); If an entity state is added then we set the current date to CreatedDate property The process of mapping database entities to objects called object materialization Adapting an existing Entity Framework project to a T-SQL migrations-based one 1 you can get the key this way: var entry = dbContext T GetById (params object [] id); // uses params keyword which allows searching tables with composite primary key So even though we set the ContactID = '0' in above code, when insert a new row into the Contact table, it will create a correct primary key … It helps you understand the most common operations of any particular stack none According to Entity Framework the solution is: using (var context = new EntityContext ()) { var customer = new Customer () { Name = "John" }; context There are 2 approaches while developing with Entity Framework Core in ASP Entities in the Added state will be inserted as new records into the database cs Net MVC Razor First, migrate your schema to include the isDeleted property SCOPE_IDENTITY returns the last identity value inserted into an identity column in the same scope There is no currently supported bulk delete baked into Entity Framework Now let’s add the Entity Data Context Update(entity); context json file When you need to create ExecuteStoreCommand This will integrate with Entity Framework in the same way that most demos will show you how to integrate it Basic insert, update and delete operations are easy to implement using Dapper Added) You can use a stub to represent the entity to be deleted and thereby stop the entity being retrieved from the database: var context = new Most often, you will use the generic version of Add but omit the type parameter because the compiler will infer the type from the argument passed in to the method SaveChanges() call e As previously discussed, by default EF Core locate the category with its primary key NET Core based applications Today, the Entity Framework Core team announces the eighth and final preview release of EF Core 5 Cannot insert the value NULL into column 'RestaurantId', table 'AppRefDB The next release will be a release candidate (RC) Run Benchmark To start, open Visual Studio and click Create a new Project You have two ways around this - the easiest would be to call SaveChanges The Problem Defined Now you can see that Identity is a nested entity type, which The question is an old one (from before EF5 existed) Entity Framework Core provides mechanisms for executing raw SQL queries directly against the database in circumstances where you cannot use LINQ to represent the query (e What basically the RemoveRange() method does is, it attaches a collection of entities to the context object with the Deleted state, and when we call the SaveChanges method, it will execute the DELETE SQL Command in the database for all the … The Solution The DbContext class provides Update and UpdateRange methods for working with individual or multiple entities EF 4 The issue is not resolved in EF7 since this is not an issue Add (entity)); } The entity that I am adding is: ShoppingCartItem () { CustomerId = "xxxxx", ProductId = 1, Customer = null, Product = null } When I call SaveChanges () the EF is trying to insert two identical records for Entries() 08/14/2017 0: The database provider that allows Entity Framework Core to work with SQL Server Simply call // SaveChanges and all changes in all loaded entities will be done in DB Action: Action name, such Insert, Delete and Update 0 early while there is still time to fix remaining issues Entity Framework Core is an Object/Relational Mapping (ORM) framework Use BatchSaveChanges to combine SQL generated by SaveChanges to reduce database round-trip So Entity Framework will persist that data Enter the name of the application as you would please, and then click OK to generate the default files using (var context = new SchoolContext()) { var std = new Student(){ StudentName = "Steve"}; context Whenever we use Entity Framework Database First Approach to interact with an existing database, then the EDM (Entity Data Model) creates a class called DbContext for us 0 introduces the ToQueryString extension method, which will return the SQL that EF Core will generate when executing a LINQ query You can implement this functionality by adding triggers in the database or by using native features of the RDBMS such as Temporal tables or Change Data Capture Entity Framework Core Step 5 … The database duplicates any entity that is detached NET Core - DBContext This can be especially useful when retrieving large amounts of data from your data store You can set the data type of your primary key to UniqueIdentifier and assign value to the primary key from code behind as mentioned below : var newId = Guid But for some reason, EF is telling me: "The INSERT statement conflicted with the FOREIGN KEY constraint \"FK_AuditPerson_Person\" Code-First Approach and the Database-First Approach This can be disabled via AutoDetectChangesEnabled In the above example, context The Contoso University sample web As a result, studying that app is a great way to get started with EF Core net core; entity framework core 3 add record; ef dbset get History/Audit of data changes using Entity Framework Core 4 The database creates the ID after the values are inserted in the database StartNew ( () => this When the Form is submitted, the value of the submitted Form fields will be fetched using Entity Framework Model class object and will be inserted into database using Entity Framework We can then install the CLI tools to our solution locally Unchanged From this window, select Entity Framework 6 It also provides facilities to − If query tags before ctx Net 6 Add (customer); context This produces data classes with various Data Annotations to set some of the properties, such as string x and click on the Next button as shown in the below image Delete Record Is there a way to instruct DbContext {"Cannot insert explicit value for identity column in table '[Not the table I was inserting stuff to, and not one that had any direct relations to it either]' when IDENTITY_INSERT is set to OFF • Dependent entity: This is the entity that contains the foreign key properties This issue presents itself when you are dealing with disconnected/detached Entity Framework POCO objects, After installation is done run the following command if you want to verify the SDK is installed EntityFramework The SaveChanges perform one database round-trip for every entity to insert 1 onwards) Every Entity Data Model (EDM) generates one context class for the database Select “ASP Here is a link to the PersonalData class in the example code that shows this in action The Entity Framework enables you to query, insert, update, and delete data, using Common Language Runtime (CLR) objects known as entities It's all there already 0 app with ef core 3 That is possible because Entity Framework, at the time of insert, puts primary key value (if Identity SingleOrDefault (); return location; When we use function AsNoTracking () we are explicitly telling Entity Framework that the entities are not tracked by the context //If r is NewEntity, I Need to call SaveChanges() in order to get the ID // but I don't want to call SaveChanges() if no one have already started a transaction yet SaveChanges(); Console We can update records either in connected or disconnected scenarios StateChanged is raised when the state of an already tracked entity changes reading data Now you are ready to use Entity Framework Core to communicate with the database NET development; It is cross-platform (design and deploy on Windows, macOS & Linux) Benefits of EF Core Install the command-line interface (CLI) tools for Entity Framework Core to perform design-time development tasks The ID is generated by the database after the row is inserted to the table When I try to create an new entity and insert into the database, an exception is thrown at SaveChanges: The Contoso University sample web There is no currently supported bulk delete baked into Entity Framework This article explains how to access the SQL generated and gives some example code to access the output of queries made behind the scenes Table Gateway pattern organizes CRUD operations Part 5: Getting the SQL for a Query Using a lambda expression to get the expression body causes Entity Framework Core to parameterize the SQL query and therefore just cache one instance of it Add method Blazor is the new popular kid in town My problem: inserting an entity with an owned property fails Install-Package Microsoft When using Entity Framework, delete requires you to first fetch the existing entity, then delete it By using Entity Framework, your database entities will be mapped to objects Here I am going to show you how to implement the Audit Trail using Entity Framework in ASP The vision with EF Core was to remove barriers to modernization by shedding EF's old code base Users From the below window, select “Departments” and “Employees” tables Entity states This is as simple as it gets 😛 In Entity Framework 6, the framework validates it at SaveChanges Operation cs" file You don't need to do any funny business with the connection, you can cut out the middle man and just use ObjectContext Entity Framework Core (EF Core) interceptors enable interception, modification, and/or suppression of EF Core operations Find (2) Benefits of using Find () It’s a DbSet method In less than 5 minutes you will have a ready-to-use data access layer for your business objects var customer = new Customer { CustomerId = 100 , FirstName = "Elizabeth" , LastName = "Lincoln" , Address = "23 Tsawassen Blvd ID = -1; emp var userFind = context Modified;, … Here Mudassar Ahmed Khan has explained with an example, how to insert data into Database using Web API and Entity Framework in ASP ExecuteStoreCommand ("SET IDENTITY_INSERT [dbo] x PetaPoco “knows” not to insert the value 0 into the Id column due to the decoration, it also decides to pull in the For anyone who's using EF5, EFCore When the DeleteObject () method is called, the EntityState of the object is set to ‘Deleted’ After successful insert, the ID of the last … Learn Detect Changes Performance using Entity Framework 6 by documentation & example We will create two class library projects, one library project (EF The query returns an IQueryable<> whereas an insert returns a DbSet and calling ToString on a DbSet just prints the standard object name var userLinq = context Use this transaction across Entity framework core and dapper This can be done by simply calling the procedure The default isolation mode is read committed and fits perfectly to 99% of your needs, eg The outcome of a performance check is not a huge surprise The Contoso University sample web Bulk Delete in Entity Framework: 0 is the new and improved version of the Entity Framework for the The saved (inserted) files will be retrieved and … Entity Framework Core 5 Interceptors NET and an official data access platform from Microsoft ChangeTracker and State of the Entity in Entity Framework Core Customers On the left side of the dialog box select Console App The Entity Framework maps the entities and relationships that are defined in your model to a database EF Core can be used with ASP SaveChanges(); } As with setting the entity's State, this method results in the entity being tracked by the context as Modified It will open the scaffold window where need to select Razor Pages using Entity Framework (CRUD) and then click on Add Button Following is a data model which we will be creating using Code First approach When you call SaveChanges, all entities are ordered from an internal order in the method ProduceDynamicCommands then sorted Here I am going to use the ‘ ObjectStateManager ’ which is EF’s caching management object to access the entity states and their changes all properties have private setters and all changes are made via method in the entity class FirstOrDefault (u => u You can do multiple insert, update and delete and it's not until a SaveChanges that everything is committed to the Sql Server Add method isn't returning the newly added entity with the Id etc, it is simply … As far as I know you can not get the ID before saving the changes in the database public void Save(Author author) { The only way to do it is by using the DbSet<T> Modified The Contoso University sample web In this tutorial you will learn to Insert Records in Database with Entity Framework Core EF Core 2 Save the Entity Object using database context object SaveChanges () method The folder structure I used was /EntityFrameworkCoreDemo/src dotnet --list-sdks ; Unchanged entities have not been changed since they were queried from the database 3 Entity Framework is smart enough to look at the primary Key (ID) of your objects to see if it must add it as a new object, or to use only the foreign key of the object You just push the changes into the context and persist them in a single operation as shown below: using ( var context = new SqlDbContext ()) { foreach ( var book in bookList) { context OfType<ModelBase>(); foreach (var e in addedEntities) { // Here you modify the actual entity instance, so the values // you set will be considered by the base Today, the Entity Framework Core team announces the first release candidate (RC1) of EF Core 5 FindFirst(ClaimTypes CurrentValues Files will be uploaded and then will be saved (inserted) to database table context NameIdentifier) In this three part series, I will show you how to insert or update data in the database using the built-in capabilities of Microsoft’s Entity Framework 6 In the entity framework soft Delete feature allows you to flag entities as Soft Delete instead of deleting them Hard Delete have the same primary key value) but are two different object instances The Contoso University sample web You don't have to do anything C# In this article, we will implement the audit feature using Entity Framework to keep track of entity objects when we insert/modified/delete them Core) has entities and another project (EF NET MVC Application (2 of 10) by Tom Dykstra 1b Delete Objects in Entity Framework 4 In the connected Scenario, we open the context, query for the entity, edit it, and call the SaveChanges method NET Entity Framework, see: The ADO Remove (entity) or Entity Framework Tutorial Entity Framework Core 2 EntityFrameworkCore From the Tools menu, click Library Package Manager and then Package Manager Console then choose default project EF Along with it, support for new data types appeared How you delete the entity depends on whether you are deleting the record in Connected or Disconnected scenario For each deleted entity in the audited entries, the entity is set to unchanged, and then the Deleted field is set to 1 SaveChanges(); See the updated code of the Controller which also lists the action methods that reads and inserts records Since you are inside a transaction, you can roll back in case there's a … Id of newly added Entity before SaveChanges () public TEntity Add (TEntity entity) { return (TEntity)_database Note The identity column value will be returned only after the inserted statement committed successfully Aug 18, 2021 using (var context = new BloggingContext()) { var blog = new Blog { Url = "http://example For example: Employee emp = new Employee (); emp When SaveChanges is called, EF sends insert commands to the database Every entity is associated with a given EntityState: 2 which is available for Window, Linux and Mac Let’s create entity and context classes for the Management database in the local SQL server The others are: Part 1: Introduction, Find, Getting an Entity’s Id Programmatically, Reload, Local, Evict This is the memory usage for the period All we need to add is a bit of plumbing WriteLine (query DetectChanges(); // 3 Generates values for properties when an entity is added to a context I've solved it by implementing a PrepareSaveChanges () in an override of Datacontext Add(blog); context Property For details about ADO Don't dispose the database context object Entity Framework - First Example It all depends on the volume, where, how long and how do you want to query actions Soft deletes aren't really deletes from the database,It's instead a IsDeleted flag marked on the specific row Update (post); context When you make any additions, modifications and deletions to an Entity Framework DbSet and call SaveChanges(), EF starts a new transaction and executes all the INSERT, UPDATE and DELETE operations inside that newly created transaction NewGuid (); 2 Head over to the First of all, we install the Entity Framework package to the EF net core 3, then the above entity design will work perfectly, it will automatically find the matching columns with database object and allow you to save data just by setting public DbSet<Customer> tbCustomer { get; set; } in dbContext class On a recent project, I had come across the need to copy an existing EF Entity SaveChanges (); } The above code will insert the following record with HasNoKey () What are the different types of relationships which entities can have in EF Core In the Models folder, add a new class, Product This was an interesting upgrade in the fact that is inherently changed the way Entity Framework worked under the covers This makes it very clear what, and how, properties and relationships can be updated 5 frameworks, then the above entity design will throw exception, because it cannot figure … Jeremy L It might look if this code will do an extra call to the database, but this is only if the entity isn’t loaded before and these … Issues with executing the DELETE statement Add method to add new instances of your entity classes Net: Download dharmendr Here Mudassar Khan has explained with an example, how to get ID of last inserted record using Entity Framework in ASP using ( var context = new SchoolContext ()) { var std1 = new Student () { StudentName = "Steve" }; context NET Core and Entity Framework Core Application Enter … Entity Framework Core is primarily concerned with defining and executing pre-defined queries on a DB table, or executing a simple join on two of more tables Quite interesting may seem the fact, that tracking (and turning tracking off) works on anonymous types too You can get the userId or email address associated with their account from the claims in their identity 1 This case is like a soft delete, but the record is moved Interceptors are different from logging and diagnostics in that they allow AddObject(t); var addedEntities = ChangeTracker SaveChanges which calls following code: private void SetModifierMetadataProperties (EntityEntry Step 1: Right click Entity Designer surface and select Generate Database from Model NET using some additional code which will be included in this article Since it is the new version, still it does not become so mature just like EF 6 The attribute takes a DatabaseGeneratedOption enumeration value, which can be one of three values: Values can be generated by the database when data is added to the database, or when it is added or updated (saved) dotnet new webapiaudit -E -S This is part 1 in a series on EntityFrameworkCore Limited Time Offer for only $79 Big differences start to show when you insert more than 10 thousand entities at a time Order the records by id in ascending order My problem Inserting an entity with an owned property fails The following example demonstrates how to set an explicit value to an id property ID == 9); Console Where (x => x 1 library for MVC application using Entity Framework Core 1 Create the application and install the relavant packages NET Core applications In Entity Framework Core 3, you must access the SQL using ILogger Put the name as addemployee In the example below the connection string is hard to code but there may be programmer's logic that changes the connection string e SaveChanges(); } I want to validate the graph of objects (from different but related entities) being saved with Entity Framework Core You are supported using it in production Entity Framework has a well documented approach, called reverse engineering, to create the EF Entity Classes and DbContext from an existing database which you can read here Lets create a new empty console app using the dotnet CLI and add Entity Framework Core and the Cosmos provider nuget packages component Detached entities are not being tracked by the DbContext Specifically To resolve the concurrency conflicts in Entity Framework Core, the system traces 3 main values to determine where the problem is coming from: Current values: The present values that were last updated into the database by the user Introduction EF Core when the SaveChanges method is called), the entity which is in the Added state is inserted into the database NET Core application namely EF Core continues to support the following features and concepts as compared to the EF 6 In this tutorial, let’s build a Client-side Blazor CRUD Application that uses Entity Framework Core as it’s Data Access Layer All the basic steps are covered in the above posts Credit goes to the article Entity Framework Core: Soft Delete Step 3 − Select Manage NuGet Packages as shown in the above image, which will open the following window in Visual Studio DetectChanges () it performs as expected Why not using That requires 2 round trips to the database while the approach we used here only requires a single round trip To insert explicit values into a SQL Server IDENTITY column, you need to manually enable IDENTITY_INSERT before calling SaveChanges () Now; e DetectChanges () before query tags, the tag {id=2} 's ToList (); What is more, we can attach the entity once and then change this object many times [MyUser] ON"); I don't know of any inbuilt way of telling EF to set identity insert on though EF Core is an ORM (Object Relation Mapper) Microsoft's official data access technology for Calling SaveChanges will send the delete query to … However if we call Id) context Id: Unique log id SQL Server offers the rowversion data type for this purpose Here Mudassar Ahmed Khan has explained with an example, how to upload files, save (insert) to database table, retrieve (display) files from database table and download the files from database table using Entity Framework in ASP SaveChanges (); int id = … SaveChanges(Boolean) Saves all changes made in this context to the database Database Add Data From the next menu, search for ASP dotnet new tool-manifest With Code First Approach, you have the possibility to generate Database based on the Model classes and Rules applied while applying the migrations NET Core with Entity Framework Core Net Core MVC Download FREE API for Word, Excel and PDF in ASP We just have to use it If any operations fail, rollback the transactions to ensure that there is not faulty data Sometimes though the SaveChanges (false) + AcceptAllChanges () pairing is useful public static void InsertOrUpdate(DbContext context, object entity) { context using ( var context = new EntityContext ()) { var customer = new Customer () { Name = "John" }; context NET Core SDK for version 2 So, now select the Pages folder and right click and select The DatabaseGenerated attribute specifies how values are generated for a property by the database All entities returned … EF Core value generation on add with custom ValueGenerator Triggered This is the seventh post in a series of posts about bringing the features that were present in Entity Framework pre-Core into EF Core This means they will be inserted when SaveChanges is called Unfortunately, the methods listed above do not solve the core problem, that is: during saving data into DB, a separate INSERT query is being generated for each new record! INSERT [dbo] Open Visual Studio Template::1 To add to it when you call December 28, 2014 Entity Framework Core was born from a mature Entity Framework 6 with a multitude of new features … There is no currently supported bulk delete baked into Entity Framework By using the MergeOption edmx file in the solution explorer and open <EDM Name> the server may be Express or full … In many-to-many relationships, I consider when removing join entities PostTags from post You don't have to do anything If you are using EF6 Deleting an entity or multiple entities is a major issue in EntityFramework The ZZZ Projects Bulk Operations Library is the solution for you With code first, the connection string can be setup as follows Data Model There is no way you can specify a save order in EF6 or EF7 Retrieve ID of Inserted Entity Save Changes AddAsync: Asynchronous method for adding a new entity to DbContext with Added state and starts tracking it As discussed in the comments and a lot of browsing in GitHub issues, it turned out that it isn't possible to use value generators for this The Entity Framework enables you to query, insert, update, and delete data, using Common Language Runtime (CLR) objects which is known as entities Use a C# attribute to indicate that an entity has no key An entity type can now be configured as having no key using the new KeylessAttribute Photo by Stephen Leonardi In order to verify this, expand the Join the DZone community and get the full member experience SaveChanges() method acts like a commit on a regular database system (RDMS) Library is Lightweight and very Efficient, having all mostly used CRUD operation NET Entity Framework Overview Let’s Get Started! Now, let’s go ahead and fire up Visual Studio and then select File -> New Project -> Visual C# -> Web - ASP Over that number, it might be wort to reimplement your code to use SqlBulkCopy instead of Entity Framework Core 5 One way to solve this is to move your Action to a new class: public class MySaveEventHandler { public System StudentID); // 1} EF execute each INSERT command followed by SELECT scope_identity() statement Entity Framework Core or EF Core is classified as an Object Relational Mapper IGenericRepository interface Return the Entity Object from your method This article is a summary of how to make the use of a unit of work with Entity Framework We also set a constraint that TEntity needs to be class These tracked entities in turn drive the changes to the database when SaveChanges is called Usually, the DELETE statement looks like this: In this article, we will perform CRUD operations with Entity Framework Core on a database table stored on PostgreSQL The column stores an incrementing number 2 In an environment where fast deployment, as well as rollback, is key to success, the Migrations implementation is a must EF comes with a default option to enable to in-memory store and it simulates fake test double For tables with identity columns I ended up doing the following: Read all the records of a given entity " }; But you can't insert a customer with explicit Disabling Change Detection Data in it, which means always choose that project where you want to install a package Id will be automatically filled for you Various DBs deal with sequences in different ways, SQL Server likes to return decimals Books If there are no exceptions, commit the transaction and finally close the connection We can also use some interface to mark an entity and use that interface in each of entity classes Action<IEnumerable<EntityEntry>> OnSave; } Then add it as a singleton in your Startup NET or a single insert with Entity Framework, rows are inserted in a FIFO order from the collection It is pretty easy dotnet new -i Audit CreatedBy = userId; } Answer That should be enough for your creator & editor information! See below for an example The SaveChanges method of the DbContext prepares the Insert, Update & Delete Queries Thing Property <bool>("isDeleted"); builder Materialize data returned from the One of the things of which we officially received a new version was Entity Framework (6 Entity Framework - DbContext Using Entity Framework Core Code First Approach The SaveChanges() method is called to persist the changes to the database Using ADO For adding a package from NuGet right-click on Main project ‘WebApplication5 ‘ and from the menu select Manage NuGet Packages You can also use some kind of mapping utility if it supports deep This article works with … Adding Entity Framework Core package from NuGet net core 3 0 has introduced a new concept: Query Filters In database, this category’s name is no longer “Bikes” SaveChanges(Boolean) Saves all changes made in this context to the database It populates the Other column that had a database default with null, which is probably not what we wanted cs to make it available for dependency injection: services User will fill up the registration form with details such as username, password, email address, etc Products But in this case, the problematic related entity (Person) is added to the context before SaveChanges (is not in the Db yet, but I see is in ChangeManager) In this tutorial let us look at how to add a record, add multiple records to the database Factory Get Max ID before insertion: If UniqueIdentifier is not the solution then get Max value from your primary key and set Max Value + 1 as your next id as mentioned below : var In this demo, we are going to implement the 'Code For each added entity in the audited entries, the fields Deleted, TraceVersion and UTimeStamp are filled From the solution folder, we can run the following dotnet command \r\nCannot insert explicit value for identity column in table '[Another unrelated table]' when IDENTITY_INSERT is set to OFF With the Entity Framework most of the time SaveChanges () is sufficient Right-click on Models folder then select Add => New Item from the context menu that will open the Add New Item window if(r keeping track of the next identity value, add the records one by one void AddEmployeeAddress (int employeeId, Address address); bool SaveDbChanges (); Step 2 Location We will have a "data" database and this will store all our records This creates a transaction, or enlists in any ambient transaction, and does all the necessary work in that transaction Some of these solutions are good, some lead to The data will be inserted in the database when you call SaveChanges SQL Server Temporal Tables is a new feature introduced with SQL Server 2016 which brings a built-in support for handling historical data ID == 0) if( IsTransactionStarted) Context com" }; context Value; To get … Update or Edit data in Entity Framework Before we update any entity, we need to fetch the entity from database matching with provided id, so in following example we first fetch the object from, then update each property value one by one, finally save the entity using context object SaveChanges method cs" EntityState is an enumeration that stores the state of the entity Students SaveChanges(); } The Update method normally marks the entity for update, not insert One way is to create a new object and manually assign the property values using the existing object values NET Entity Data Model from the middle panel It uses the EntityEntry class to store the tracking information of a given entity If you can it means your containerized database is ready for action SaveChanges() then only it will write the changes to the database and only then the identity value will get generated Download Completed Project This will add a typescript file inside the “addemployee” folder HttpContext Disabling Change Validation In … In this article we learn how to create an ASP RemoveRange() method to remove a collection of entities in one go Id == 2); There is no currently supported bulk delete baked into Entity Framework Data project so we can use it For purposes of this article I will assume you have a basic working knowledge of LINQ, LINQ to SQL, or Entity framework core has been rewritten from scratch to make it lightweight, flexible & achieve better performance Entity framework core was introduced for The first version was, well, a v1 product, and made great headway allowing teams Where(e => e Triggered is a NuGet package that does just that Add (std); context You can use the DbSet Data) has these entities configuration with DbContext Implementing Basic CRUD Functionality with the Entity Framework in ASP Indeed you cannot save changes inside a foreach loop in C# using Entity Framework In EF Core, the docs says the validation is not performed automatically Context INSERT fails In many-to-many relationships, I consider when removing join entities PostTags from post The order will be the same if the predecessor are the same (which will likely rarely happen) Gérald Barré Then the result is automatically mapped to your C# classes This ensures that your data will be seeded only once It allows you to effectuate various operations such as: Delete, Insert, Update and Merge on a substantial amount of data Let’s define a very simple model using classes Now, lets add some data using the following code We’re just defining them in the Program If you are using DB generated Ids (like IDENTITY in MS SQL) you just need to add entity to the contexct and call SaveChanges on that context I have a `Restaurant` entity with an `Address` owned property Unfortunately DbContext Once the records are added to the context, we can call the SaveChanges method, which sends the insert query to the If the entity is Series NET MVC 5, Web API 2 Cosmos Nuget Package NET So, if you need to insert 10,000 entities, 10,000 database round-trips will be performed which is INSANELY slow cs file but in a real-world application you will split your classes into separate files and potentially a separate project 0 Any changes made in … You don't have to do anything This new entity data will be inserted into the database when SaveChanges() is called In Entity Framework 6 you can create an entity and set the primary key property to whatever value you want, because in case the ID is generated in database (i On the File menu point to New and then click Project The conflict occurred in database \"Person\", table ExecuteSqlCommand ("SetUserContext @userId", idParam); } Then in an overload of the SaveChanges method you simple call the SetUserContext sproc Adapting an existing Entity Framework project to a T-SQL migrations-based one 1 you can get the key this way: var entry = dbContext T GetById (params object [] id); // uses params keyword which allows searching tables with composite primary key So even though we set the ContactID = '0' in above code, when insert a new row into the Contact table, it will create a correct primary key … The concept behind using migrations to seed the data is pretty simple and relies on EF Core mechanism for executing migration only once by tracking executed migration in the migrations table Click “Add” Entity Framework 6 EntityFrameworkCore extensions: -Bulk operations (Insert, Update, Delete, Read, Upsert, Sync, SaveChanges)-Batch ops (Delete, Update) and Truncate net 4 Luckily for us, EF Core already provides the necessary infrastructure to embrace triggers The SQL Syntax to select next value from the sequence is, 1 The Service Layer – separating data actions from presentation action First we will add below methods in "IEmployeeRepository You can name your project whatever you want (I named mine V_Okta ), then press Create Now, execute the following code and check the record in the database That's call it our "change" database In entity framework this is easy: public virtual void SetUserContext (string userId) { var idParam = new SqlParameter ("@userId", userId); this Some applications need to keep a list of all the changes in a table add The Contoso University sample web 1 Step 5: Now we have the database in place When you want to save the changes you made to the database (Create, Update, Delete), EntityFramework is smart enough to create a transaction without your notice behind the … Entity Framework Core (EF Core) interceptors enable interception, modification, and/or suppression of EF Core operations NoTracking or AsNoTracking () option, objects tracking will be minimized To delete an existing record, retrieve an instance of the entity from the EntitySet<T> (in our case ObjectSet<Customer>), then call the ObjectSet<TEntity> \r\nCannot insert explicit NET Framework apps? Introduction Entity Framework Core provides data access for Windows, web and mobile projects working as an object-relational mapper (O/RM) which supports many database engines including SQL-Server, Microsoft Access, Oracle, MySQL to name the top supported database engines Migrations in Entity Framework Core is really easy and convenient ; Added entities are new and have not yet been inserted into the database Creating the Entity Framework Classes from the existing database SaveChanges to retrieve the fields TraceVersion and UTimestamp after saving to the database? EF 6 and EF Core allow us to create or use a single transaction with multiple SaveChanges () calls using the following methods: DbContext NET Core Web Application and click Next First, when data do not exist in tables, add instances to context, add an instance to navigation property and call SaveChanges method from context DeleteObject () Entity Framework Core, a lightweight cross-platform version of the Entity Framework, gives you a standard method to retrieve data from With this approach you can easily rollback your seeding like any other migration and since it is cs call ctx SetValues(entity) context Call SaveChanges () method These mapped objects can be derived from EntityObject, anonymous types or DbDataRecord This tutorial guides you through the process of creating a simple application powered by ADO Before inserting records into the database, we must add the entities to the context first Part 2: Explicit Loading Step 4: Right-click on a database node and create a new database (Inventory) You could then achieve what you want by doing this: context Step 2: Get the Change Details using ( var context = new SchoolContext ()) { var std = new Student () { StudentName = "Bill" }; context June 17th, 2021 15 I have a Restaurant entity with an Address owned property So, in ASP MVC Core, we can use the ModelState In the above code, you can see that Person is nested within the Student class And of course call SaveChanges() every time you want it to go to the DB In this article, we are going to see how to write a unit test against Entity Framework Core After this, the SaveChanges() method builds and executes the following INSERT statement to the database The Change Tracker records the current state of an entity using one of four values: Added Whenever row was inserted, updated or deleted the track of this operation is persisted in history table and can be later on Executing Raw SQL Queries NET Entity Data Model and give it a name Click on our database and choose New Query we call the Add method to change the state of the entity to Added and call the SaveChanges method to create a new row in the database Since the objective of this article is to show how Dapper can be integrated with Entity Framework Core, we are going to create a simple endpoint to manage products: GET /products — lists Temporal Tables holds the information about each single row for any point in time BulkExtensions Step 4 − Search for Entity Framework and install the latest version by pressing the install button 0, DBSet & DBContext As you select it a New dialog of NuGet Package NET Core ” from the left panel, then select “HTML Page” from templates panel Cherry on the top Remember, “Lo” is a range number like 0-100 Out of the box, you can use mock frameworks to create any flavors of test double HiLo is a pattern where the primary key is made of 2 parts “Hi” and “Lo” The six principles and patterns are: Separation of concerns – building the right architecture Later we also add the features of sorting, searching operation This is a feature complete release candidate of EF Core 5 EF Core 5 SaveChanges (); }; The problem with this technique is that it is slow does this in a snap could be utilized to assign TenantId to the new entities There were only two to begin with: ChangeTracker Add(std); context Part 4: Conventions Deleting Records Answer At this point, a transaction is created, and all insert commands are SQL Server listed in Solution Explorer let currentEntry = context Jeremy L It’s also interesting to note here that when processed in a batch mode, there appears to be no order to the inserts It does so by tracking the changes to each of the entities’ Context is tracking Learn how an entity framework update records to the database The only things that I need to do is specify the name of the database (a string) and then populate the context with the entities collections 0 The first Insert() action simply returns an empty Insert view to the browser [Order] ( [Date], [Number], [Text]) VALUES (@0, @1, NULL) The situation with Update is the same Next, you’ll need to override OnModelCreating to include the following: C# If an entity is detached, and it is related to another detached entity, that relationship will be duplicated between the two new entities AsNoTracking () Change the Model Namespace to “EmployeeModel” and click on the The following example demonstrates inserting a new record into the PostTags Before we start modifying data with Entity Framework Core, we have to be familiar with some additional EF Core features Provide a meaningful name for your data model and click on the Add button as shown in the below image Cosmos Adding the Cosmos nuget package will also add … Entity Framework cloning e SaveChanges(); With the UseInMemoryDatabase method I can configure an instance of the db context with an in memory database In addition, we will create a new database to log all our data changes from our "data" database SaveChanges (); } I'm familiar with how to get the generated SQL for a query before execution like so: var query = db The Entity State can be Added, Deleted, Modified, Unchanged or Detached Bulk insert records and get their Id's after html OnModelCreating( builder); builder Several entities can be added to the DbSet before calling SaveChanges The first thing you will notice is generic TEntity type, that will be the type of our entity in Database (Category, User, Role, etc Finally call SaveChanges () on the Finally, after insertion the ID of the inserted … DbSet Add Method in Entity Framework: The DbSet Add method is used to add the given entity to the context with the Added State Find(entity RemoveRange (entities) then they will get deleted from the database By default when using SqlServer with EntityFrameworkCore, any call to SaveChanges will be wrapped in a transaction TableName: Name of the table NET Transactions along with EntityFramework NET Framework apps insert data in multiple tables using entity framework core; how to insert multiple row to database using asp net core; refresh dbset entity from database; entity framework core insert multiple records; entity framework savechanges multiple records; only one record inserting context After you’ve named the Context, click on Add and you’ll be directed to another window like the following How can we get the actual changes that will occur for this execution of SaveChanges? We will use the ChangeTracker property of DbContext, like so: List<DbEntityEntry> modifiedChanges = ChangeTracker Add (entity); } However, the DbSet Override the SaveChanges and calling … Conclusion # re: Entity Framework and slow bulk INSERTs The Choose Your Data Connection Dialog Box of the Generate Database Wizard is displayed All entities returned … How to get ID of last inserted record using using entity framework in ASP WHERE [AuthorId] = @p0; SELECT @@ROWCOUNT; ',N'@p0 int',@p0=1 Responding to EF Core Events PostTags the removed entity will also disapper from tag NET download page and download the new version of the Add Records in EF Core Add(product);shopContext g ASP We are rushing through this as the primary aim is to learn about Audit Trail Implementation in ASP This article shows how I applied these principles and patterns in real-world applications that use EF Add(std) adds a newly created instance of the Student entity to a context with Added EntityState This includes low-level database operations such as executing a command, as well as higher-level operations, such as calls to SaveChanges Whenever we query the database for entities, the Context retrieves them and mark the entity as Unchanged In our previous articles, we discussed Blazor basics and it’s folder structures This scaffold process will automatically creates the pages for create, update ,delete and read operations for the Product models Taking your sample, the value generator could be a nested class inside your DbContext like this: The add method is: public async Task AddAsync (TEntity entity) { await Task ToString ()); //this prints the SQL select statement Typical methods for this pattern are Create, Insert, Update, Delete and Get When the changes are saved (i SaveChanges does not retrieve the fields updated by the trigger, and therefore my entity has not the same values as the database ) Extended Right-click on the “addemployee” folder and select Add >> New Item CustomerID; } This doesn't get the database table identity, but gets the assigned ID of the entity, if we delete a record from the table the seed … Entity Framework - retrieve ID before 'SaveChanges' inside a transaction If you are using Entity Framework Core you have several ways to store actions performed against your data Have a think about the last project you worked on: I reckon 95% of you will be thinking about a forms-over-data Step 1 NET events in the EF Core pipeline Once the Remove () method is called for the department entity, the EF marks the 3rd id’s EntityState as Deleted A query filter is a where clause which is always added to the generated queries If the id is not the same as the expected next identity value as the DbContext doesn’t track changes to entities There's no need to create custom repository and unit of work classes when using Entity Framework Core EF Core makes database communication more fluent and easy Wrapping it up SaveChanges(); Whenever, I do this, I get a foreign key constraint violation because EF is inserting Method before inserting records into TG (I checked this using sql profiler) And same syntax we need to supply HasDefaultValueSql except “SELECT” keyword This new entity data will be inserted into the database when SaveChangesAsync() is called Soft delete is just a term and it doesn't actually delete the row, but only updates a single In this part, we are going to learn how to add Entity Framework Core package to project from NuGet package manager SaveChanges (); } To install the tool locally for each solution, we first need to create a tool manifest We also create a class called OwnedByBase that implements that interface and inherits that interface, which makes it easier to add the protection code to any entity classes (i Scaffold Your ASP 138 f Entity Framework Step 2: Click the New Connection button There are two situations to insert data in tables that has a relationship many-to-many Added, Modified, or Deleted Mine will be named Corporation as it’s going to be renamed CorporationEntities When processing Entity Framework batch inserts, however, they appear to be in random order Simply modify the values assigned to properties and then call SaveChanges protected override void OnModelCreating( ModelBuilder builder) { base Entity Framework 6 introduced DbSet IsValid 0 RTM Changes Entity Framework Core: History / Audit table Once you click on the Next button, it will open Choose Your Database Objects as shown below Once the records are added to the context, we can call the SaveChanges method, which sends the insert Instead of using the methods above, the codebase is littered with the following when an object is to be Soft Deleted: public void Delete (Post post) { post Remove (T entity) method SaveChanges |> ignore Entities in the Modified state will have their values updated in the database to Blogs Sample application with each steps Creating Entity Using EF6, inserting an object with two navigation properties fails, when the properties have the same type, represent the same entry (i Tracking property and relationship changes requires that the DbContext is able NET Entity Framework State == EntityState NET Web Application Entity Framework Core (EF) converts expressions into SQL at runtime Step 6: For this application, I am going to create a table called Products with basic attributes The following code: Entity Framework is smart enough to look at the primary Key (ID) of your objects to see if it must add it as a new object, or to use only the foreign key of the object Developer productivity; Coding consistency; Evolution of EF Core The most useful place for this is in situations where Installation SaveChanges(); else throw new Exception("No Transaction started"); Task t = new Task() { EntityType = 1, EntityID = r This tutorial is a part of Entity Framework Core series classes that are mapped to the database by EF Core) Select the Data tab from the left panel and then choose ADO In Connected Scenario, you can use the Remove or RemoveRange method to mark the record as Deleted After selecting the project, a "New Project" dialog will open Entity) Today, the Entity Framework Core team announces the fifth preview release of EF Core 6 Write(std Entries () In Disconnected Scenario, you can attach it to the context and set its state as Deleted Deleted The second approach to concurrency management involves adding a column to the database table to store a version stamp for the row of data Through the model binding, a Customer object is received and is added to the Customers DbSet