Get started with the MySQL Pomelo Entity Framework Core integrations

MySQL is an open-source Relational Database Management System (RDBMS) that uses Structured Query Language (SQL) to manage and manipulate data. It's employed in many different environments, from small projects to large-scale enterprise systems and it's a popular choice to host data that underpins microservices in a cloud-native application. The Aspire Pomelo MySQL Entity Framework Core integration enables you to connect to existing MySQL databases or create new instances from .NET with the mysql container image. Entity Framework Core (EF Core) is an object-database mapper that simplifies data access by allowing developers to work with databases using .NET objects.

In this introduction, you'll see how to install and use the Aspire MySQL Pomelo Entity Framework Core integrations in a simple configuration. If you already have this knowledge, see MySQL Hosting integration and MySQL Pomelo Entity Framework Core Client integration reference for full reference details.

Set up hosting integration

To begin, install the Aspire MySQL Hosting integration in your Aspire AppHost project. This integration allows you to create and manage MySQL database instances from your Aspire hosting projects:

dotnet add package Aspire.Hosting.MySql

Next, in the AppHost project, create instances of MySQL server and database resources, then pass the database to the consuming client projects:

var builder = DistributedApplication.CreateBuilder(args);
  
var mysql = builder.AddMySql("mysql")
                   .WithLifetime(ContainerLifetime.Persistent);
  
var mysqldb = mysql.AddDatabase("mysqldb");
  
var exampleProject = builder.AddProject<Projects.ExampleProject>("apiservice")
                            .WaitFor(mysqldb)
                            .WithReference(mysqldb);

Use the integration in client projects

Now that the hosting integration is ready, the next step is to install and configure the client integration in any projects that need to use it.

Set up client projects

In each of these consuming client projects, install the Aspire MySQL Pomelo EF Core client integration:

dotnet add package Aspire.Pomelo.EntityFrameworkCore.MySql

In the Program.cs file of your client-consuming project, call the AddMySqlDbContext extension method on any IHostApplicationBuilder to register a DbContext for use through the dependency injection container. The method takes a connection name parameter.

builder.AddMySqlDbContext<MyDbContext>("mysqldb");

Use injected MySQL properties

In the AppHost, when you used the WithReference method to pass a MySQL database resource to a consuming client project, Aspire injects several configuration properties that you can use in the consuming project.

Aspire exposes each property as an environment variable named [RESOURCE]_[PROPERTY]. For instance, the Uri property of a resource called mysqldb becomes MYSQLDB_URI.

Use the GetValue() method to obtain these environment variables in consuming projects:

var connectionUri = builder.Configuration.GetConnectionString("mysqldb");
var host = builder.Configuration.GetValue<string>("MYSQLDB_HOST");
var databaseName = builder.Configuration.GetValue<string>("MYSQLDB_DATABASENAME");

Use MySQL resources in client code

Now that you've added the DbContext to the builder in the consuming project, you can use the MySQL database. Get the DbContext instance using dependency injection. For example, to retrieve your data source object from an example service, define it as a constructor parameter and ensure the ExampleService class is registered with the dependency injection container:

public class ExampleService(MyDbContext context)
{
    // Use MySQL DB Context...
}

Having obtained the data context, you can work with the MySQL database as you would in any other C# application using EF Core.

Next steps

Now that you have an Aspire app with MySQL Pomelo EF Core integrations up and running, you can use the following reference documents to learn how to configure and interact with the MySQL resources: