Unleashing the Power of Visual Studio 2017 for Data Access Layer Development

As a developer, you’re probably aware that the task of creating and managing data access can be both complex and time-consuming. Lucky for you, Microsoft has revolutionized the art of data access layer development with Visual Studio 2017! In this article, we will explore the ins and outs of data access layers, why they’re essential for application development, and how you can create one robust layer using Visual Studio 2017.

Understanding Data Access Layers

A data access layer is a software layer that sits between your application code and the database, adding a whole new level of complexity and functionality. Simply put, the primary purpose of a data access layer is to facilitate communication with relational databases and allow developers to interact with the database using objects and methods, thus abstracting the details of the database.

The Business Case for Data Access Layers

It’s a no-brainer that data access layers come with a plethora of benefits, chief among them being:

• Separation of concerns: data access layers segregate database-related code, making it easier to maintain and debug.
• Code reuse: data access layers enable reuse of code across multiple applications, leading to increased consistency and speedier development.
• Performance: data access layers optimize database queries, making them faster for better application performance.
• Security: data access layers add an extra layer of security by enforcing authentication and authorization rules.

Creating a Data Access Layer in Visual Studio 2017

Having established why data access layers are critical for application development, let’s now delve into how you can create one in Visual Studio 2017 from scratch:

Step 1: Create a .NET Core Project

Launch Visual Studio 2017 and create a new .NET Core project. Select the corresponding project type, such as “ASP.NET Core Web Application.”

Step 2: Install Entity Framework Core

To use Entity Framework Core for our data access layer, we need to install it first. In the “Solution Explorer,” right-click on the project, and select “Manage NuGet Packages.”

On the “Browse” tab, search for “Microsoft.EntityFrameworkCore” and install the latest version of the framework.

Step 3: Define Your Model Class

You need to define a model class that represents a corresponding database table. For instance, if you have a “Product” table in your database, create a new folder named “Models” in your project and add a new class named “Product.cs” to the folder. The class would have the following structure:

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }
}

Step 4: Create a DbContext Class

The DbContext class manages database connections and transactions. Create a folder named “Data” in your project and add a new class named “AppDbContext.cs” to the folder. The class should inherit from the DbContext class and have the following structure:

public class AppDbContext : DbContext
{
    public AppDbContext(DbContextOptions<AppDbContext> options) : base(options) { }

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

Step 5: Configure the Database Connection

The next step involves configuring the database connection. In the “Startup.cs” file, add the code below to the “ConfigureServices” method:

string connectionString = Configuration.GetConnectionString("DefaultConnection");
services.AddDbContext<AppDbContext>(options => options.UseSqlServer(connectionString));

The code retrieves the database connection string from the appsettings.json file and configures the AppDbContext with it.

Step 6: Create a Repository Class

Create a repository class that interacts with the database and performs CRUD operations. In your project, create a folder named “Repositories” and add a new class named “ProductRepository.cs” to the folder. The class should have the following structure:

public class ProductRepository
{
    private readonly AppDbContext _context;
    public ProductRepository(AppDbContext context)
    {
        _context = context;
    }
    public IEnumerable<Product> GetAllProducts()
    {
        return _context.Products.ToList();
    }
    public Product GetProductById(int id)
    {
        return _context.Products.FirstOrDefault(p => p.Id == id);
    }
    public void AddProduct(Product product)
    {
        _context.Products.Add(product);
        _context.SaveChanges();
    }
    public void UpdateProduct(Product product)
    {
        _context.Products.Update(product);
        _context.SaveChanges();
    }
    public void DeleteProduct(int id)
    {
        Product product = _context.Products.FirstOrDefault(p => p.Id == id);
        if (product != null)
        {
            _context.Products.Remove(product);
            _context.SaveChanges();
        }
    }
}

In this class, methods are defined to retrieve, add, update and delete products from the database.

Step 7: Use the Repository Class

Now that we have created the repository class, we can put it to use in our application. In the product controller, we need to inject the AppDbContext and the ProductRepository as shown:

public class ProductController : Controller
{
    private readonly AppDbContext _context;
    private readonly ProductRepository _repository;
    public ProductController(AppDbContext context, ProductRepository repository)
    {
        _context = context;
        _repository = repository;
    }
    // Actions go here
}

We can then call methods from the repository class to perform CRUD operations:

public IActionResult Index()
{
    IEnumerable<Product> products = _repository.GetAllProducts();
    return View(products);
}
public IActionResult Details(int id)
{
    Product product = _repository.GetProductById(id);
    if (product == null)
    {
        return NotFound();
    }
    return View(product);
}
public IActionResult Create()
{
    return View();
}
[HttpPost]
public IActionResult Create(Product product)
{
    if (ModelState.IsValid)
    {
        _repository.AddProduct(product);
        return RedirectToAction(nameof(Index));
    }
    return View(product);
}
public IActionResult Edit(int id)
{
    Product product = _repository.GetProductById(id);
    if (product == null)
    {
        return NotFound();
    }
    return View(product);
}
[HttpPost]
public IActionResult Edit(Product product)
{
    if (ModelState.IsValid)
    {
        _repository.UpdateProduct(product);
        return RedirectToAction(nameof(Index));
    }
    return View(product);
}
public IActionResult Delete(int id)
{
    Product product = _repository.GetProductById(id);
    if (product == null)
    {
        return NotFound();
    }
    return View(product);
}
[HttpPost, ActionName("Delete")]
public IActionResult DeleteConfirmed(int id)
{
    _repository.DeleteProduct(id);
    return RedirectToAction(nameof(Index));
}

In conclusion

Voila! Creating a data access layer in Visual Studio 2017 using Entity Framework Core is as easy as pie! Through a data access layer, developers can keep database-related code separate from the rest of the application code, making it a breeze to maintain and debug. That’s not all; data access layers enable optimized database queries and, consequently, enhance the performance of applications. So go ahead and unleash the power of Visual Studio 2017 for a top-tier data access layer.