In this article I will explain a simple tutorial with an example, how to use Entity Framework Core with Database First Approach in ASP.Net Core 7.
Database First Approach means, first the Database is configured and then it is connected to Application using Entity Framework Core.
This article will explain, how to configure Entity Framework Core and connect to SQL Server database in ASP.Net Core 7.
Note: For beginners in ASP.Net Core 7, please refer my article ASP.Net Core 7: Hello World Tutorial with Sample Program example.
 
 
Database
Here I am making use of Microsoft’s Northwind Database. You can download it from here.
Download and install Northwind Database
Note: The Customers Table of the Northwind Database will be used in this project.
 
 
Downloading Entity Framework Core
You will need to install the Microsoft.EntityFrameworkCore.SqlServer package using the following command.
Install-Package Microsoft.EntityFrameworkCore.SqlServer -Version 7.0.15
 
 
Model
1. Once the package is successfully installed, create a Folder named Models in your project and then a new class by right clicking the Models folder and then click on Add and then New Item option of the Context Menu.
.Net Core 7: Entity Framework Database First Approach
 
2. Create the following properties inside the Model class as shown below.
Note: In this article, only four Columns will be displayed and hence four properties are added to the class.
 
public class Customer
{
    public string CustomerID { get; set; }
    public string ContactName { get; set; }
    public string City { get; set; }
    public string Country { get; set; }
}
 
 
Database Context
1. Now you will need to add a new class to your project by right clicking the Solution Explorer and then click on Add and then New Item option of the Context Menu.
.Net Core 7: Entity Framework Database First Approach
 
2. Inside the class, first inherit the EntityFrameworkCore namespace and then inherit the DbContext class.
Then, using Dependency Injection, a Constructor is created DbContextOptions are passed as parameter and also the Constructor of base class i.e. DbContext class is inherited.
Finally, a DbSet Collection property of Customer Model class is created, which will be later used for holding the Data fetched from SQL Server Database Table.
using EF_Core_7_MVC.Models;
using Microsoft.EntityFrameworkCore;
namespace EF_Core_7_MVC
{
    public class DBCtx : DbContext
    {
        public DBCtx(DbContextOptions<DBCtx> options) : base(options)
        {
        }
 
        public DbSet<Customer> Customers { get; set; }
    }
}
 
 
Adding the Connection String inside AppSettings.json
The following Connection String setting has been added in the AppSettings.json file.
{
 "ConnectionStrings": {
    "MyConn": "Data Source=.\\SQL2022;Initial Catalog=Northwind;Integrated Security=True"
 }
}
 
 
Configuring Database Context in Program.cs
Inside the Program.cs file, the Connection String is read from the AppSettings.json file and is used to add the DbContext service to the WebApplicationBuilder class.
Note: For more details on reading Connection String inside the Program.cs file, please refer my article .Net Core 7: Read Connection String inside Program.cs from AppSettings.json file.
 
using EF_Core_7_MVC;
using Microsoft.EntityFrameworkCore;
 
var builder = WebApplication.CreateBuilder(args);
 
// Enabling MVC
builder.Services.AddControllersWithViews();
string conStr = builder.Configuration.GetSection("ConnectionStrings")["MyConn"];
builder.Services.AddDbContext<DBCtx>(options => options.UseSqlServer(conStr));
 
var app = builder.Build();
 
//Configuring Routes
app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");
 
app.Run();
 
 
Controller
The Controller consists of following Action method.
Action method for handling GET operation
Inside this Action method, the Top 10 records are fetched from the Customers Table of the Northwind Database and returned to the View.
public class HomeController : Controller
{
    private DBCtx Context { get; }
    public HomeController(DBCtx _context)
    {
        this.Context = _context;
    }
 
    public IActionResult Index()
    {
        List<Customer> customers = (from customer in this.Context.Customers.Take(10)
                                    select customer).ToList();
        return View(customers);
    }
}
 
 
View
Inside the View, in the very first line the Customer Entity is declared as IEnumerable which specifies that it will be available as a Collection.
For displaying the records, an HTML Table is used. A loop will be executed over the Model which will generate the HTML Table rows with the Customer records.
@using EF_Core_7_MVC.Models;
@model IEnumerable<Customer>
 
@{
    Layout = null;
}
 
<!DOCTYPE html>
<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
</head>
<body>
    <h4>Customers</h4>
    <hr/>
    <table cellpadding="0" cellspacing="0">
        <tr>
            <th>CustomerID</th>
            <th>ContactName</th>
            <th>City</th>
            <th>Country</th>
        </tr>
        @foreach (Customer customer in Model)
        {
            <tr>
                <td>@customer.CustomerID</td>
                <td>@customer.ContactName</td>
                <td>@customer.City</td>
                <td>@customer.Country</td>
            </tr>
        }
    </table>
</body>
</html>
 
 
Screenshot
.Net Core 7: Entity Framework Database First Approach
 
 
Downloads
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