Using Entity Framework Core for Data Access & Relational Mapping/

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Adding, Updating, and Deleting Data

Adding, Updating, and Deleting Data

Learn the basics of adding, updating, and deleting data in EF Core.

We'll cover the following...

Overview

In this lesson, we’ll learn how to add, update, and delete data using EF Core. Each context instance has a ChangeTracker. When we make changes to instances of the entities, the ChangeTracker keeps track of those changes.

An entity is always in a specific state. For example, new entities are in the Added state (EntityState.Added) and modified entities are in the Modified state (EntityState.Modified), while those to be deleted are in the Deleted state (EntityState.Deleted). When we call the DbContext.SaveChanges() method, EF Core builds and executes the required INSERT, UPDATE, or DELETE statements for entities based on the values of their EntityState.

The projects in this lesson include the data in the table below:

Employees

Id

FirstName

LastName

Age

1

Max

Bello

25

2

Francis

Ojukwu

34

3

Martha

Bertha

19

Albums

Id

Title

Price

EmployeeId

1

Blue Fire

2000

2

2

Raging Heart

3850

3

3

Fixated on you

4000

1

Note: The outputs from the projects in this lesson contain the results of the sample codes and logs from the translated SQL queries used.

Adding data

We’ll demonstrate adding data in EF Core using the C# project below:

using Microsoft.EntityFrameworkCore;

namespace SaveData
{
    public partial class ArtistsContext : DbContext
    {
        public ArtistsContext() { }

        public ArtistsContext(DbContextOptions<ArtistsContext> options) : base(options) { }

        public virtual DbSet<Employee> Employees { get; set; }
        public virtual DbSet<Album> Albums { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            if (!optionsBuilder.IsConfigured)
            {
                optionsBuilder
                    .UseSqlite("data source=output/Artists.db")
                    .LogTo(
                        Console.WriteLine,
                        new[] { DbLoggerCategory.Database.Command.Name },
                        Microsoft.Extensions.Logging.LogLevel.Information
                    ).EnableSensitiveDataLogging();
            }
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
        }
    }
}
Adding data

Click the “Run” button above, then ...