EF Core Providers Getting Started

SQL Server Provider

Microsoft SQL Server is a relational database management system (RDBMS) that supports various transaction processing, business intelligence, and analytic applications in corporate IT environments.

• You can install SQL Server provider by installing the Microsoft.EntityFrameworkCore.SqlServer NuGet package.
• It allows Entity Framework Core to be used with Microsoft SQL Server (including SQL Azure).

Install Entity Framework Core

Let's create a new application using the Console App (.NET Core) template and install the following NuGet package.

In the Package Manager Console window, enter the following command.

PM> Install-Package Microsoft.EntityFrameworkCore

You can also install this NuGet package by right-clicking on your project in Solution Explorer and select Manage Nuget Packages....

Search for Microsoft.EntityFrameworkCore and install the latest version by pressing the install button.

Register EF Core Provider

For SQL Server LocalDB, which is installed with Visual Studio, we need to install Microsoft.EntityFrameworkCore.SqlServer and will get all the packages required for EF Core.

PM> Install-Package Microsoft.EntityFrameworkCore.SqlServer

Now, you are ready to start your application.

Create Data Model

Model is a collection of classes to interact with the database.

• A model stores data that is retrieved according to the commands from the Controller and displayed in the View.
• It can also be used to manipulate the data to implement the business logic.

To create a data model for our application, we will start with the following two entities.

public class Author
{
    public int AuthorId { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public DateTime BirthDate { get; set; }
    public List<Book> Books { get; set; }
}

public class Book
{
    public int BookId { get; set; }
    public string Title { get; set; }
    public Author Author { get; set; }
}

There's a one-to-many relationship between Author and Book entities. In other words, an author can write any number of books, and only one author can write a book.

Create Database Context

The database context class provides the main functionality to coordinate Entity Framework with a given data model.

• You create this class by deriving from the System.Data.Entity.DbContext class.
• In your code, you specify which entities are included in the data model.
• You can also customize certain Entity Framework behaviors.

So, let's add a new BookStore class that will inherit the DbContext class.

public class BookStore : DbContext
{
    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer(@"Data Source=(localdb)\ProjectsV13;Initial Catalog=BookStoreDb;");
    }
        
    public DbSet<Author> Authors { get; set; }
    public DbSet<Book> Books { get; set; }
}

In EF Core, the DbContext has a virtual method called OnConfiguring that will get called internally by EF Core.

• It will pass in an DbContextOptionsBuilder instance, which can be used to configure options for the DbContext.
• The DbContextOptionsBuilder has the UseSqlServer method, which expects a connection string as a parameter.

Create Database

Now, to create a database using migrations from your model, install the following packages

PM> Install-Package Microsoft.EntityFrameworkCore.Tools
PM> Install-Package Microsoft.EntityFrameworkCore.Design

Once these packages are installed, run the following command in Package Manager Console.

Add-Migration Initial

This command scaffold a migration to create the initial set of tables for your model. When it is executed successfully, then run the following command.

Update-Database

This command applies the new migration to the database and creates the database before applying migrations.

You can also create a database on run time using the following code.

using (var context = new BookStore())
{
    context.Database.EnsureCreated();
    // more 
}

Now, we are done with the required classes and database creation, let's add some authors and book records to the database and then retrieve them.

using (var context = new BookStore())
{
    context.Database.EnsureDeleted();
    context.Database.EnsureCreated();
    var authors = new List<Author>
    {
        new Author
        {
            FirstName ="Carson",
            LastName ="Alexander",
            BirthDate = DateTime.Parse("1985-09-01"),
            Books = new List<Book>()
            {
                new Book { Title = "Introduction to Machine Learning"},
                new Book { Title = "Advanced Topics on Machine Learning"},
                new Book { Title = "Introduction to Computing"}
            }
        },
        new Author
        {
            FirstName ="Meredith",
            LastName ="Alonso",
            BirthDate = DateTime.Parse("1970-09-01"),
            Books = new List<Book>()
            {
                new Book { Title = "Introduction to Microeconomics"}
            }
        },
        new Author
        {
            FirstName ="Arturo",
            LastName ="Anand",
            BirthDate = DateTime.Parse("1963-09-01"),
            Books = new List<Book>()
            {
                new Book { Title = "Calculus I"},
                new Book { Title = "Calculus II"}
            }
        }
    };

    context.Authors.AddRange(authors);
    context.SaveChanges();
}

using (var context = new BookStore())
{
    var list = context.Authors
        .Include(a => a.Books)
        .ToList();

    foreach (var author in list)
    {
        Console.WriteLine(author.FirstName + " " + author.LastName);

        foreach (var book in author.Books)
        {
            Console.WriteLine("\t" + book.Title);
        }
    }
}

If you run the application, you will see that authors and books are successfully inserted into the database and also printed on the console.

Carson Alexander
        Introduction to Machine Learning
        Advanced Topics on Machine Learning
        Introduction to Computing
Meredith Alonso
        Introduction to Microeconomics
Arturo Anand
        Calculus I
        Calculus II

You can also view the inserted data in the database in SQL Server Object Explorer.