Using EfCore

EF Core + MySQL (Code First) - Quick Cheat Sheet

0) Prerequisites

• .NET SDK installed (dotnet --info)
• A MySQL server you can connect to

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1) Install the EF CLI tool (dotnet-ef)

Needed for dotnet ef migrations ... commands.

dotnet tool install --global dotnet-ef
# update later if needed:
dotnet tool update --global dotnet-ef

Verify:

dotnet ef --version

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2) Install required NuGet packages (EF Core + MySQL)

Recommended provider: Pomelo.EntityFrameworkCore.MySql

As of writing this document (2026-02-27) the current stable Pomelo.EntityFrameworkCore.MySql package (9.0.0) requires Microsoft.EntityFrameworkCore and Microsoft.EntityFrameworkCore.Design packages in version 9.0.13.

dotnet add package Microsoft.EntityFrameworkCore
dotnet add package Microsoft.EntityFrameworkCore.Design
dotnet add package Pomelo.EntityFrameworkCore.MySql

Microsoft.EntityFrameworkCore.Design is required for migrations tooling.

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3) Add a simple entity + DbContext (default mapping)

Example entity (User.cs)

public class User
{
    public int Id { get; set; }              // default PK by convention
    public string Name { get; set; } = "";   // default string mapping
}

DbContext (AppDbContext.cs)

using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;
 
public class AppDbContext : DbContext
{
	private const string CONNECTION_STRING = 
	"server=localhost;port=3306;database=yourdb;user=youruser;password=yourpassword";
 
	public DbSet<User> Users { get; set; }; // DbSet for the entity
    
	protected override void OnConfiguring(DbContextOptionsBuilder options)  
		=> options.UseMySql(  
				CONNECTION_STRING,  
				ServerVersion.AutoDetect(CONNECTION_STRING))
			.LogTo(Console.WriteLine, LogLevel.Information) // 👈 log SQL  
			.EnableSensitiveDataLogging() // 👈 include parameter values (dev only!)  
			.EnableDetailedErrors();
}

Default conventions (no attributes/fluent mapping yet):

• Id or <TypeName>Id becomes the primary key
• Table name commonly matches the DbSet name (e.g., Users)

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4) Create your first migration

From the project directory (the one containing the .csproj):

dotnet ef migrations add InitialCreate

Useful flags:

# if your startup project differs from the project containing DbContext
dotnet ef migrations add InitialCreate --project ./DataProject --startup-project ./ConsoleProject

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5) Apply migrations to the database

dotnet ef database update

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6) Handy EF CLI commands

dotnet ef dbcontext info
dotnet ef dbcontext list
dotnet ef migrations list
dotnet ef migrations remove          # removes last migration (if not applied)
dotnet ef database drop -f           # drops database (DANGEROUS)

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7) Use the context in the app

using var dbContext = new AppDbContext();
List<string> userNames = dbContext
	.Users
	.Select(u => u.Name)
	.ToList();