ASP.NET Core Complete Course: Module 5 – Mastering Data Access with Entity Framework Core for Modern Web Development

 

Welcome to Module 5 of our ASP.NET Core Complete Course: Beginner to Advanced Guide for Modern Web Development. In this module, we dive deep into Data Access in ASP.NET Core, focusing on Entity Framework Core (EF Core), a powerful Object-Relational Mapping (ORM) framework. This comprehensive guide covers the introduction to EF Core, database migrations, CRUD operations, using LINQ with EF Core, the Repository Pattern and Unit of Work, and connecting to SQL Server, MySQL, and PostgreSQL.

Table of Contents

1. Introduction to Data Access in ASP.NET Core

2. Introduction to Entity Framework Core

   • What is Entity Framework Core?

   • Benefits of EF Core

   • Setting Up EF Core

3. Database Migrations

   • What are Database Migrations?

   • Creating and Applying Migrations

   • Example: Setting Up Migrations

4. CRUD Operations with EF Core

   • What are CRUD Operations?

   • Implementing CRUD Operations

   • Example: Building a CRUD Application

5. Using LINQ with EF Core

   • What is LINQ?

   • LINQ Queries with EF Core

   • Example: Querying Data with LINQ

6. Repository Pattern & Unit of Work

   • What is the Repository Pattern?

   • What is Unit of Work?

   • Example: Implementing Repository and Unit of Work

7. Connecting with SQL Server, MySQL, PostgreSQL

   • Configuring Different Databases

   • Example: Connecting to Multiple Databases

8. Best Practices for Data Access in ASP.NET Core

9. Conclusion

10. FAQs

---

Introduction to Data Access in ASP.NET Core

Data access is a critical component of modern web applications, enabling interaction with databases to store, retrieve, update, and delete data. In ASP.NET Core, Entity Framework Core (EF Core) is the preferred tool for data access, providing a robust and efficient way to work with databases using an Object-Relational Mapping (ORM) approach.

In Module 5, we’ll explore:

• Entity Framework Core: An introduction to EF Core and its setup.

• Database Migrations: Managing database schema changes.

• CRUD Operations: Creating, reading, updating, and deleting data.

• LINQ with EF Core: Querying data efficiently.

• Repository Pattern & Unit of Work: Structuring data access for maintainability.

• Connecting to Databases: Working with SQL Server, MySQL, and PostgreSQL.

This blog post is example-driven, with step-by-step guides and real-world scenarios to make data access concepts accessible. By the end, you’ll be able to build scalable, data-driven applications with EF Core.

Why is this important?

• EF Core: Simplifies database interactions with a high-level, object-oriented API.

• Migrations: Automate database schema management.

• CRUD Operations: Form the foundation of data-driven applications.

• LINQ: Enables powerful and readable database queries.

• Repository Pattern: Promotes clean and testable code.

• Multiple Databases: Supports flexibility in database choices.

Let’s dive into each topic with detailed explanations and practical examples.

---

Introduction to Entity Framework Core

What is Entity Framework Core?

Entity Framework Core (EF Core) is a lightweight, extensible, and cross-platform ORM framework for .NET. It allows developers to interact with databases using C# objects, abstracting away the complexities of raw SQL queries.

Key Features

• Object-Relational Mapping: Maps database tables to C# classes (entities).

• Cross-Platform: Runs on Windows, macOS, and Linux.

• Multiple Database Support: Works with SQL Server, MySQL, PostgreSQL, SQLite, and more.

• LINQ Integration: Enables querying databases using Language Integrated Query (LINQ).

• Change Tracking: Automatically tracks changes to entities for updates.

• Migrations: Manages database schema changes.

Benefits of EF Core

• Productivity: Simplifies data access with less boilerplate code.

• Maintainability: Uses C# models, making code easier to understand and maintain.

• Testability: Supports dependency injection for unit testing.

• Performance: Optimized for efficient database queries.

• Flexibility: Supports multiple databases and custom configurations.

Setting Up EF Core

To use EF Core, you need to:

1. Install the necessary NuGet packages.

2. Define entity classes and a database context.

3. Configure the database provider and connection string.

Example: Setting Up EF Core

Let’s set up EF Core with SQL Server in an ASP.NET Core MVC project.

Step 1: Create a New MVC Project

dotnet new mvc -o MyDataApp
cd MyDataApp

Step 2: Install EF Core PackagesAdd the following NuGet packages:

dotnet add package Microsoft.EntityFrameworkCore.SqlServer
dotnet add package Microsoft.EntityFrameworkCore.Design

Step 3: Define the ModelCreate Models/Product.cs:

namespace MyDataApp.Models
{
    public class Product
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public decimal Price { get; set; }
        public string Category { get; set; }
    }
}

Step 4: Create the Database ContextCreate Data/AppDbContext.cs:

using Microsoft.EntityFrameworkCore;
using MyDataApp.Models;

namespace MyDataApp.Data
{
    public class AppDbContext : DbContext
    {
        public AppDbContext(DbContextOptions<AppDbContext> options) : base(options)
        {
        }

        public DbSet<Product> Products { get; set; }
    }
}

Step 5: Configure EF CoreUpdate appsettings.json:

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=localhost;Database=MyDataAppDb;Trusted_Connection=True;MultipleActiveResultSets=true"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*"
}

Update Program.cs:

using Microsoft.AspNetCore.Builder;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using MyDataApp.Data;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddControllersWithViews();
builder.Services.AddDbContext<AppDbContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));

var app = builder.Build();

// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Home/Error");
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseRouting();
app.UseAuthorization();

app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");

app.Run();

This sets up EF Core with SQL Server, ready for migrations and CRUD operations.

---

Database Migrations

What are Database Migrations?

Database Migrations in EF Core allow you to create and update the database schema based on your entity models. Migrations generate SQL scripts to apply changes like creating tables, adding columns, or modifying constraints.

Key Concepts

• Migration Files: C# classes that define schema changes.

• Apply Migrations: Updates the database to match the model.

• Rollback: Reverts changes if needed.

Creating and Applying Migrations

1. Install EF Core Tools:

   dotnet tool install --global dotnet-ef

2. Create a Migration:

   dotnet ef migrations add InitialCreate

3. Apply the Migration:

   dotnet ef database update

Example: Setting Up Migrations

Let’s create and apply migrations for the Product model.

Step 1: Create the Initial MigrationRun:

dotnet ef migrations add InitialCreate

This generates a migration file in the Migrations folder, e.g., 202508201618_InitialCreate.cs.

Step 2: Inspect the MigrationThe generated migration file will look like this:

using Microsoft.EntityFrameworkCore.Migrations;

namespace MyDataApp.Migrations
{
    public partial class InitialCreate : Migration
    {
        protected override void Up(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.CreateTable(
                name: "Products",
                columns: table => new
                {
                    Id = table.Column<int>(type: "int", nullable: false)
                        .Annotation("SqlServer:Identity", "1, 1"),
                    Name = table.Column<string>(type: "nvarchar(max)", nullable: true),
                    Price = table.Column<decimal>(type: "decimal(18,2)", nullable: false),
                    Category = table.Column<string>(type: "nvarchar(max)", nullable: true)
                },
                constraints: table =>
                {
                    table.PrimaryKey("PK_Products", x => x.Id);
                });
        }

        protected override void Down(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.DropTable(name: "Products");
        }
    }
}

Step 3: Apply the MigrationRun:

dotnet ef database update

This creates the MyDataAppDb database and a Products table in SQL Server.

Step 4: Verify the DatabaseUse a tool like SQL Server Management Studio (SSMS) to confirm the Products table exists with columns Id, Name, Price, and Category.

---

CRUD Operations with EF Core

What are CRUD Operations?

CRUD stands for Create, Read, Update, Delete—the four basic operations for managing data in a database. EF Core simplifies CRUD operations by providing a high-level API to interact with the database.

Implementing CRUD Operations

• Create: Add a new entity to the database.

• Read: Retrieve entities from the database.

• Update: Modify existing entities.

• Delete: Remove entities from the database.

Example: Building a CRUD Application

Let’s build an MVC application to perform CRUD operations on the Product entity.

Step 1: Create a ControllerCreate Controllers/ProductsController.cs:

using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using MyDataApp.Data;
using MyDataApp.Models;
using System.Threading.Tasks;

namespace MyDataApp.Controllers
{
    public class ProductsController : Controller
    {
        private readonly AppDbContext _context;

        public ProductsController(AppDbContext context)
        {
            _context = context;
        }

        // GET: Products
        public async Task<IActionResult> Index()
        {
            return View(await _context.Products.ToListAsync());
        }

        // GET: Products/Create
        public IActionResult Create()
        {
            return View();
        }

        // POST: Products/Create
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Create(Product product)
        {
            if (ModelState.IsValid)
            {
                _context.Add(product);
                await _context.SaveChangesAsync();
                return RedirectToAction(nameof(Index));
            }
            return View(product);
        }

        // GET: Products/Edit/5
        public async Task<IActionResult> Edit(int? id)
        {
            if (id == null) return NotFound();
            var product = await _context.Products.FindAsync(id);
            if (product == null) return NotFound();
            return View(product);
        }

        // POST: Products/Edit/5
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Edit(int id, Product product)
        {
            if (id != product.Id) return NotFound();

            if (ModelState.IsValid)
            {
                try
                {
                    _context.Update(product);
                    await _context.SaveChangesAsync();
                }
                catch (DbUpdateConcurrencyException)
                {
                    if (!_context.Products.Any(e => e.Id == id)) return NotFound();
                    throw;
                }
                return RedirectToAction(nameof(Index));
            }
            return View(product);
        }

        // GET: Products/Delete/5
        public async Task<IActionResult> Delete(int? id)
        {
            if (id == null) return NotFound();
            var product = await _context.Products.FindAsync(id);
            if (product == null) return NotFound();
            return View(product);
        }

        // POST: Products/Delete/5
        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> DeleteConfirmed(int id)
        {
            var product = await _context.Products.FindAsync(id);
            _context.Products.Remove(product);
            await _context.SaveChangesAsync();
            return RedirectToAction(nameof(Index));
        }
    }
}

Step 2: Create ViewsCreate Views/Products/Index.cshtml:

@model List<MyDataApp.Models.Product>

<h1>Products</h1>
<p><a asp-action="Create" class="btn btn-success">Create New</a></p>
<table class="table">
    <thead>
        <tr>
            <th>Name</th>
            <th>Price</th>
            <th>Category</th>
            <th></th>
        </tr>
    </thead>
    <tbody>
        @foreach (var product in Model)
        {
            <tr>
                <td>@product.Name</td>
                <td>@product.Price</td>
                <td>@product.Category</td>
                <td>
                    <a asp-action="Edit" asp-route-id="@product.Id">Edit</a> |
                    <a asp-action="Delete" asp-route-id="@product.Id">Delete</a>
                </td>
            </tr>
        }
    </tbody>
</table>

Create Views/Products/Create.cshtml:

@model MyDataApp.Models.Product

<h1>Create Product</h1>
<form asp-action="Create" method="post">
    <div class="form-group">
        <label asp-for="Name"></label>
        <input asp-for="Name" class="form-control" />
        <span asp-validation-for="Name" class="text-danger"></span>
    </div>
    <div class="form-group">
        <label asp-for="Price"></label>
        <input asp-for="Price" class="form-control" />
        <span asp-validation-for="Price" class="text-danger"></span>
    </div>
    <div class="form-group">
        <label asp-for="Category"></label>
        <input asp-for="Category" class="form-control" />
        <span asp-validation-for="Category" class="text-danger"></span>
    </div>
    <button type="submit" class="btn btn-primary">Create</button>
</form>

@section Scripts {
    <script src="~/lib/jquery-validation/dist/jquery.validate.min.js"></script>
    <script src="~/lib/jquery-validation-unobtrusive/jquery.validate.unobtrusive.min.js"></script>
}

Create Views/Products/Edit.cshtml (similar to Create.cshtml but with asp-action="Edit").

Create Views/Products/Delete.cshtml:

@model MyDataApp.Models.Product

<h1>Delete Product</h1>
<h3>Are you sure you want to delete this?</h3>
<div>
    <h4>@Model.Name</h4>
    <p>Price: $@Model.Price</p>
    <p>Category: @Model.Category</p>
    <form asp-action="Delete" method="post">
        <input type="hidden" asp-for="Id" />
        <button type="submit" class="btn btn-danger">Delete</button>
        <a asp-action="Index" class="btn btn-secondary">Cancel</a>
    </form>
</div>

Step 3: Run the ApplicationRun the application with dotnet run and navigate to /Products. You can create, read, update, and delete products using the UI.

This example demonstrates how to implement CRUD operations using EF Core in an MVC application.

---

Using LINQ with EF Core

What is LINQ?

Language Integrated Query (LINQ) is a powerful feature in .NET that allows you to query data using C# syntax. With EF Core, LINQ queries are translated into SQL, enabling efficient database operations.

Common LINQ Operations

• Where: Filters data.

• Select: Projects data into a new form.

• OrderBy: Sorts data.

• GroupBy: Groups data.

• Join: Combines data from multiple sources.

LINQ Queries with EF Core

EF Core translates LINQ queries into SQL, executed against the database. Queries can be written using query syntax or method syntax.

Example LINQ Query

var products = _context.Products
    .Where(p => p.Price > 100)
    .OrderBy(p => p.Name)
    .Select(p => new { p.Name, p.Price })
    .ToList();

Example: Querying Data with LINQ

Let’s enhance the ProductsController to include a search feature using LINQ.

Step 1: Update ProductsController.csAdd a Search action:

public async Task<IActionResult> Search(string category, decimal? maxPrice)
{
    var query = _context.Products.AsQueryable();

    if (!string.IsNullOrEmpty(category))
    {
        query = query.Where(p => p.Category == category);
    }

    if (maxPrice.HasValue)
    {
        query = query.Where(p => p.Price <= maxPrice.Value);
    }

    query = query.OrderBy(p => p.Name);

    return View("Index", await query.ToListAsync());
}

Step 2: Update Index.cshtmlAdd a search form:

@model List<MyDataApp.Models.Product>

<h1>Products</h1>
<form asp-action="Search" method="get">
    <div class="form-group">
        <label for="category">Category</label>
        <input name="category" class="form-control" />
    </div>
    <div class="form-group">
        <label for="maxPrice">Max Price</label>
        <input name="maxPrice" type="number" step="0.01" class="form-control" />
    </div>
    <button type="submit" class="btn btn-primary">Search</button>
</form>
<p><a asp-action="Create" class="btn btn-success">Create New</a></p>
<table class="table">
    <thead>
        <tr>
            <th>Name</th>
            <th>Price</th>
            <th>Category</th>
            <th></th>
        </tr>
    </thead>
    <tbody>
        @foreach (var product in Model)
        {
            <tr>
                <td>@product.Name</td>
                <td>@product.Price</td>
                <td>@product.Category</td>
                <td>
                    <a asp-action="Edit" asp-route-id="@product.Id">Edit</a> |
                    <a asp-action="Delete" asp-route-id="@product.Id">Delete</a>
                </td>
            </tr>
        }
    </tbody>
</table>

Step 3: Test the SearchNavigate to /Products/Search?category=Electronics&maxPrice=500. The page will display filtered products sorted by name.

This example shows how to use LINQ to query data dynamically with EF Core.

---

Repository Pattern & Unit of Work

What is the Repository Pattern?

The Repository Pattern abstracts data access logic, providing a clean interface between the business logic and the database. It encapsulates CRUD operations and queries, making the code more maintainable and testable.

Benefits

• Abstraction: Hides EF Core details.

• Testability: Enables mocking for unit tests.

• Separation of Concerns: Keeps controllers thin.

What is Unit of Work?

The Unit of Work pattern coordinates multiple repository operations, ensuring they are committed as a single transaction. In EF Core, the DbContext acts as the Unit of Work, tracking changes and saving them together.

Example: Implementing Repository and Unit of Work

Let’s refactor the CRUD application to use the Repository Pattern and Unit of Work.

Step 1: Create the Repository InterfaceCreate Repositories/IProductRepository.cs:

using MyDataApp.Models;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace MyDataApp.Repositories
{
    public interface IProductRepository
    {
        Task<List<Product>> GetAllAsync();
        Task<Product> GetByIdAsync(int id);
        Task AddAsync(Product product);
        Task UpdateAsync(Product product);
        Task DeleteAsync(int id);
    }
}

Step 2: Implement the RepositoryCreate Repositories/ProductRepository.cs:

using Microsoft.EntityFrameworkCore;
using MyDataApp.Data;
using MyDataApp.Models;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace MyDataApp.Repositories
{
    public class ProductRepository : IProductRepository
    {
        private readonly AppDbContext _context;

        public ProductRepository(AppDbContext context)
        {
            _context = context;
        }

        public async Task<List<Product>> GetAllAsync()
        {
            return await _context.Products.ToListAsync();
        }

        public async Task<Product> GetByIdAsync(int id)
        {
            return await _context.Products.FindAsync(id);
        }

        public async Task AddAsync(Product product)
        {
            _context.Products.Add(product);
            await _context.SaveChangesAsync();
        }

        public async Task UpdateAsync(Product product)
        {
            _context.Products.Update(product);
            await _context.SaveChangesAsync();
        }

        public async Task DeleteAsync(int id)
        {
            var product = await _context.Products.FindAsync(id);
            if (product != null)
            {
                _context.Products.Remove(product);
                await _context.SaveChangesAsync();
            }
        }
    }
}

Step 3: Register the RepositoryUpdate Program.cs:

builder.Services.AddDbContext<AppDbContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));
builder.Services.AddScoped<IProductRepository, ProductRepository>();

Step 4: Update ProductsController.csRefactor to use the repository:

using Microsoft.AspNetCore.Mvc;
using MyDataApp.Models;
using MyDataApp.Repositories;
using System.Threading.Tasks;

namespace MyDataApp.Controllers
{
    public class ProductsController : Controller
    {
        private readonly IProductRepository _repository;

        public ProductsController(IProductRepository repository)
        {
            _repository = repository;
        }

        public async Task<IActionResult> Index()
        {
            return View(await _repository.GetAllAsync());
        }

        public IActionResult Create()
        {
            return View();
        }

        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Create(Product product)
        {
            if (ModelState.IsValid)
            {
                await _repository.AddAsync(product);
                return RedirectToAction(nameof(Index));
            }
            return View(product);
        }

        public async Task<IActionResult> Edit(int? id)
        {
            if (id == null) return NotFound();
            var product = await _repository.GetByIdAsync(id.Value);
            if (product == null) return NotFound();
            return View(product);
        }

        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Edit(int id, Product product)
        {
            if (id != product.Id) return NotFound();

            if (ModelState.IsValid)
            {
                await _repository.UpdateAsync(product);
                return RedirectToAction(nameof(Index));
            }
            return View(product);
        }

        public async Task<IActionResult> Delete(int? id)
        {
            if (id == null) return NotFound();
            var product = await _repository.GetByIdAsync(id.Value);
            if (product == null) return NotFound();
            return View(product);
        }

        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> DeleteConfirmed(int id)
        {
            await _repository.DeleteAsync(id);
            return RedirectToAction(nameof(Index));
        }
    }
}

Step 5: Test the ApplicationRun the application and verify that CRUD operations work as before, now using the Repository Pattern. This approach makes the controller cleaner and more testable.

---

Connecting with SQL Server, MySQL, PostgreSQL

EF Core supports multiple database providers, allowing you to connect to SQL Server, MySQL, PostgreSQL, SQLite, and more with minimal code changes.

Configuring Different Databases

To connect to different databases:

1. Install the appropriate EF Core provider.

2. Update the connection string in appsettings.json.

3. Configure the provider in Program.cs.

Providers

• SQL Server: Microsoft.EntityFrameworkCore.SqlServer

• MySQL: Pomelo.EntityFrameworkCore.MySql

• PostgreSQL: Npgsql.EntityFrameworkCore.PostgreSQL

Example: Connecting to Multiple Databases

Let’s configure the application to support SQL Server, MySQL, and PostgreSQL.

Step 1: Install Providers

dotnet add package Microsoft.EntityFrameworkCore.SqlServer
dotnet add package Pomelo.EntityFrameworkCore.MySql
dotnet add package Npgsql.EntityFrameworkCore.PostgreSQL

Step 2: Update appsettings.json

{
  "ConnectionStrings": {
    "SqlServerConnection": "Server=localhost;Database=MyDataAppDb;Trusted_Connection=True;MultipleActiveResultSets=true",
    "MySqlConnection": "Server=localhost;Database=MyDataAppDb;User=root;Password=your_password;",
    "PostgreSqlConnection": "Host=localhost;Database=MyDataAppDb;Username=postgres;Password=your_password"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*"
}

Step 3: Update Program.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using MyDataApp.Data;
using MyDataApp.Repositories;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddControllersWithViews();
builder.Services.AddScoped<IProductRepository, ProductRepository>();

// Choose one database provider at a time
var dbProvider = "SqlServer"; // Change to "MySql" or "PostgreSql" as needed
switch (dbProvider)
{
    case "SqlServer":
        builder.Services.AddDbContext<AppDbContext>(options =>
            options.UseSqlServer(builder.Configuration.GetConnectionString("SqlServerConnection")));
        break;
    case "MySql":
        builder.Services.AddDbContext<AppDbContext>(options =>
            options.UseMySql(builder.Configuration.GetConnectionString("MySqlConnection"),
                ServerVersion.AutoDetect(builder.Configuration.GetConnectionString("MySqlConnection"))));
        break;
    case "PostgreSql":
        builder.Services.AddDbContext<AppDbContext>(options =>
            options.UseNpgsql(builder.Configuration.GetConnectionString("PostgreSqlConnection")));
        break;
}

var app = builder.Build();

// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Home/Error");
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseRouting();
app.UseAuthorization();

app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");

app.Run();

Step 4: Create and Apply MigrationsFor each database:

dotnet ef migrations add InitialCreate --context AppDbContext
dotnet ef database update --context AppDbContext

Step 5: Test the ApplicationRun the application with each database provider by changing the dbProvider variable. The CRUD operations should work seamlessly across SQL Server, MySQL, and PostgreSQL.

---

Best Practices for Data Access in ASP.NET Core

• Use EF Core for ORM: Leverage EF Core for simplified data access.

• Apply Migrations Carefully: Test migrations in a development environment before applying to production.

• Optimize LINQ Queries: Avoid loading unnecessary data; use Select to project only required fields.

• Implement Repository Pattern: For large applications, use repositories to abstract data access.

• Use Unit of Work: Rely on DbContext as the Unit of Work for transaction management.

• Secure Connection Strings: Store connection strings securely (e.g., in Azure Key Vault).

• Handle Concurrency: Use EF Core’s concurrency handling for updates.

• Monitor Performance: Use tools like SQL Server Profiler to analyze query performance.

---

Conclusion

In Module 5 of our ASP.NET Core Complete Course, we explored Data Access in ASP.NET Core using Entity Framework Core. You’ve learned how to:

• Set up and use EF Core for data access.

• Manage database schemas with migrations.

• Implement CRUD operations in an MVC application.

• Query data efficiently using LINQ.

• Structure data access with the Repository Pattern and Unit of Work.

• Connect to SQL Server, MySQL, and PostgreSQL.

Through practical examples, you’ve built a fully functional data-driven application. In the next module, we’ll dive into advanced topics like authentication, authorization, and API development. Stay tuned!

---

FAQs

Q1: What is Entity Framework Core?

• EF Core is an ORM framework that simplifies database interactions by mapping C# objects to database tables.

Q2: How do database migrations work?

• Migrations generate SQL scripts to create or update the database schema based on changes to your entity models.

Q3: What is the Repository Pattern, and why use it?

• The Repository Pattern abstracts data access, making code more maintainable and testable by separating business logic from database operations.

Q4: Can I use EF Core with multiple databases?

• Yes, EF Core supports multiple database providers like SQL Server, MySQL, and PostgreSQL with minimal code changes.

Q5: How does LINQ improve EF Core queries?

• LINQ provides a readable, type-safe way to query databases, which EF Core translates into efficient SQL.