Sql Connector

Hello there i am trying to use my sql connector to connect to my database.
I have add the reference MySql.Data but i still getting this error from unity http://prntscr.com/njot9s
What should i do?
Thank you!

Code (CSharp):

1. using UnityEngine;
2. using MySql.Data.MySqlClient;
3.  
4. public class Test : MonoBehaviour
5. {
6.     string db = "server=localhost;" + "uid=root;" + "pwd=;" + "database=test;";
7.     // Start is called before the first frame update
8.     void Start()
9.     {
10.         try {
11.             MySqlConnection sq = new MySqlConnection(db);
12.             sq.Open();
13.         }catch (Exception er) {
14.             Debug.Log("Error");
15.         }
16.     }
17.  
18.     // Update is called once per frame
19.     void Update()
20.     {
21.        
22.     }
23. }
24.