System.data.Common.DbConnection not found

Hi !

I'm making a webGL application which is link to a MySQL database but I got an error

The error is on dbcon.Open()

Blockquote

 string conString = "*,3306;" +    /// 21 or 3306
          "Database=db;" +
          "User ID=.....;" +
          "Password=....;";

 public void TestConnection()
 {


     MySqlConnection dbcon = new MySqlConnection(conString);
     try
     {
         dbcon.Open();
     }
     catch (System.Exception)
     {
         Debug.Assert(false,"Connection fail");
     }
     Debug.Log(dbcon.State);
 }


 private void Start()
 {
     TestConnection();
 }

I'm using MySql.Data.MySqlClient and System.Data

If any of you can help me