In this article I will be sharing how we can simple CRUD app using Entity Framework Core edition which is basically an open source and cross-platform version of the Entity Framework to be used in the .Net Core application development.
With EF Core, data access is performed using a model. A model is made up of entity classes and a context object (derived from DbContext class) that represents a session with the database, allowing you to query and save data in the database.
Here I will be using code first approach without existing database.
Prerequisites
In order to develop and run .Net Core app, we need .Net Core SDK that includes .Net CLI tools, .Net Core Runtime.
So download and install the latest version of .Net Core SDK available from this link.
We will also need code editor, I will recommend VS Code but if you already have any other code editor that you are using to write C# code then stick with that otherwise download and install VS Code from this link.
After installing SDK and VS Code, open the command prompt and run following command to check if SDK installed properly.
$ dotnet --version
You must get the latest version number as a result. In my case its 3.0.101 since I had installed it sometime back.
After done with the environment setup we are ready to develop our CRUD console app.
Create a new project
Now go to the folder location where you want to create app project and open the command window.
Create console type project for our CRUD app by running following command.
$ dotnet new console -o EFCore-CrudApp
It will create EFCore-CrudApp folder with the same name project file in it.
Now we need to work under this folder so move into this folder.
$ cd EFCore-CrudApp
Add Package References
We need to install Entity Framework Core and for that we need to install the package for the EF Core database provider that we want to target. In this app we will be using SQL Server so run following command to install the Entity Framework Core.
$ dotnet add package Microsoft.EntityFrameworkCore.SqlServer --version 3.0.0
I have used specific versions compatible with .net core SDK 3.0 but if you have latest version then you should run these command without specifying the version.
You find following entry in the app project file after successful installation.
<ItemGroup>
<PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="3.0.0" />
</ItemGroup>
As we are done with our app project setup, now open VS code in the project folder to write code for this app.
Create the model
Our model will consists 2 POCO classes and a context class.
Let’s create Model.cs and create following classes to represent Member and Book entities in our Model.
public class Member
{
public int Id { get; set; }
public string Name { get; set; }
public string PhoneNo { get; set; }
public string City { get; set; }
}
public class Book
{
public int Id { get; set; }
public string Title { get; set; }
public string Gener { get; set; }
}
Also create CrudAppDbContext class derived from DbContext that represents session with the database. This class object will be used to perform crud operations on the database and its properties will represent table in the database.
public class CrudAppDbContext: DbContext
{
public DbSet<Member> Members { get; set; }
public DbSet<Book> Books { get; set; }
}
We also need to configure the database connection that will be used by the EF Migrations to sync that database with the data model in the application.
So add following code in the CrudAppDbContext class to pass the database connection while configuring the database context for this app.
protected override void OnConfiguring(DbContextOptionsBuilder options)
{
options.UseSqlServer(@"Server=(localdb)\mssqllocaldb;Database=EFCoreCrudAppDb;Trusted_Connection=True;");
}
Entity Framework Migrations
Entity Framework provides a way to create a database from the data model using Migrations. Migrations are used to keen database in sync with the changes in the application’s data model by updating the database schema while preserving existing data in the database.
So in order to create migrations we need to install Entity Framework Core tools that includes “dotnet ef” tool and the "EF designer".
Run following command in the command window to install the EF Core tools.
$ dotnet tool install --global dotnet-ef –version 3.0.0
$ dotnet add package Microsoft.EntityFrameworkCore.Design –version 3.0.0
I have used specific versions compatible with .net core SDK 3.0 but if you have latest version then you should run these command without specifying the version.
<PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="3.0.0">
<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
<PrivateAssets>all</PrivateAssets>
</PackageReference>
Create the database
Since we have installed Entity Framework Core tools, we are ready to create database from our application data model.
- First, we need to add migrations that will create the database schema of our model entities. So run following commands to create the database.
$ dotnet ef migrations add InitialCreate
It will add Migrations folder in the project with auto-generated files for “initialCreate” migration.
- Second, we need to apply “initialCreate” migration on the database. Since it’s a very first migration and we don’t have existing database so it will create new database for us.
So run following command to apply the migration to the database.
$ dotnet ef database update
A new database is created along with the tables for the model entities.
Add CRUD Operations Code
Since the database is created, we are ready to add code for crud operations.
Add new file CrudUtility.cs in the project to add crud operations code.
- Add following code to create (insert) data in the Books table in database.
public static void AddBook()
{
using (var dbcontext = new CrudAppDbContext())
{
Console.WriteLine("**********Enter Book details**********");
Console.WriteLine("--------------------------------------");
Console.Write("Book Title : ");
string title = Console.ReadLine();
Console.Write("Book Gener : ");
string gener = Console.ReadLine();
Console.WriteLine(" ");
var book = new Book { Title = title, Gener = gener };
dbcontext.Books.Add(book);
dbcontext.SaveChanges();
}
}
- Add following code to read data from the Books table.
public static void GetBooks()
{
using (var dbcontext = new CrudAppDbContext())
{
var query = from b in dbcontext.Books orderby b.Id select b;
Console.WriteLine("**********List of Books**********");
Console.WriteLine("---------------------------------");
foreach (var b in query)
{
Console.WriteLine("Details of Book No - {0}", b.Id);
Console.WriteLine("--------------------------------- ");
Console.WriteLine("Book Title - {0}", b.Title);
Console.WriteLine("Book Gener - {0}", b.Gener);
Console.WriteLine(" ");
}
}
}
- Add following code to update a particular Book data in the Books table.
Public static void UpdateBookDetails(int bookId, string title, string gener)
{
using (var dbcontext = new CrudAppDbContext())
{
var query = from b in dbcontext.Books orderby b.Id select b;
foreach (var b in query)
{
if (b.Id == bookId)
{
b.Title = title;
b.Gener = gener;
dbcontext.Update(b);
break;
}
}
dbcontext.SaveChanges();
}
}
- Add following code to delete a particular Book data from the Books table.
public static void DeleteBook(int bookId)
{
using (var dbcontext = new CrudAppDbContext())
{
var query = from b in dbcontext.Books orderby b.Id select b;
foreach (var b in query)
{
if (b.Id == bookId)
{
dbcontext.Remove(b);
break;
}
}
dbcontext.SaveChanges();
}
}
Same way add code to perform CRUD operations on “Member” entity as well.
Now we have to call these CRUD operations in our app so add following code in the Main method of Program.cs file.
CrudUtility.AddBook();
CrudUtility.GetBooks();
Console.Write("Enter Book's Id to be deleted : ");
int deletedBookId = int.Parse(Console.ReadLine());
CrudUtility.DeleteBook(deletedBookId);
Console.Write("Enter Book's Id to be updated : ");
int updatedBookId = int.Parse(Console.ReadLine());
Console.Write("Enter Book's Title : ");
string bookTitle = Console.ReadLine();
Console.Write("Enter Book's Gener : ");
string bookGener = Console.ReadLine();
CrudUtility.UpdateBookDetails(updatedBookId, bookTitle, bookGener);
You can get the complete source code from my GitHub repository EFCore-CrudApp with the details about how to setup the code on your machine.
Run the App
At last run the app with following command.
$ dotnet run
Happy reading...
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