# Connect to MySql in .NET and Entity Framework

'define expected-reading 3 min
'define created 21 May 2020
'define edited 19 June 2021
[$pagenav]

:contents
.numbered
1. [url #nuget-packages NuGet packages]
2. [url #connection-string Connection string]
3. [url #connecting Connecting]
   .numbered
   1. [url #asp.net-startup ASP.NET Startup]
   2. [url #dbcontext-child-class DBContext child class]


I have found that connecting a `[.NET]` application to a `[MySql]` database (with Entity Framework) can be tricky. Here is what works for me.

Also, [url https://www.nuget.org/packages/MySql.Data.EntityFrameworkCore/ MySql.Data.EntityFrameworkCore] has been =[depricated]= since *[October 2020]*. If you need setup instructions with it, read [url https://gitlab.com/Syndamia/syndamiadotcom/-/blob/0510e29526c6d7681587fff4c98a339e8c69e9b5/src/blog/connect-to-mysql-in-csharp-ef/article.md this].

## NuGet packages

You'll need to install [url https://www.nuget.org/packages/Pomelo.EntityFrameworkCore.MySql/ Pomelo.EntityFrameworkCore.MySql]. It provides the stuff necessary for connecting and using a `[MySql]` database.

## Connection string

There are [url https://www.connectionstrings.com/mysql/ a lot] of ways to setup the connection string but I've found that this one works the best:

```
"server=localhost; port=YOUR-PORT; user id=YOUR-USER-ID; password=YOUR-PASSWORD; database=NAME-OF-DATABASE; SslMode=none"

If you are using `[MySQL Workbench]` and you don't know your port and id, you can look at the server information from the `[MySQL Connections]` page.

[image ./img/connections.png MyServer root 127.0.0.1:3306] In this example, the user id is _root_ and the port is _3306_.

## Connecting

To connect, you'll need to call the `[UseMySql]` method, either in [url #asp.net-startup ASP.NET Startup] or in a [url #dbcontext-child-class DBContext child class].

The method requires at least two arguments: connection string and `[MySql]` server version. The latter you can find, by going to the `[Help/About Workbench]` window inside `[MySQL Workbench]`.

[image ./img/about-workbench.png]
[image ./img/workbench-version.png]

For the server version argument, create a new object of type `[MySqlServerVersion]` and give it's constructor a new object of type `[Version]`, to which you give the version numbers. The result should look something like this:

```c#
.UseMySql(CONNECTION_STRING, new MySqlServerVersion(new System.Version(8, 0, 21)))

Where `[CONNECTION_STRING]` is a (constant) variable that contains your connection string, and 8, 0, 21 are the version numbers.

### ASP.NET Startup

For `[ASP.NET]` applications, the connection must be put inside the `[ConfigureServices]` method of the `[Startup.cs]` file. If you already have a `[.UseSQL]` method call in there, just replace it with your `[.UseMySql]` method and arguments.

The result should look something along the lines of:

```c#
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
    ...
    services.AddDbContext<AppDbContext>(opt =>
    {
        opt.UseMySql(...);
    });
}

### DBContext child class

Another way to connect is via a `[DBContext]` child class (so, inside your own DB context). Just, override the `[OnConfiguring]` method and call the `[.UseMySql]` method from the `[optionsBuilder]` parameter.

```c#
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
    optionsBuilder.UseMySql(...);
}