Błąd przy kompilacji skryptu łączącego bazę danych z Unity przy użyciu connector'a MySql

Question

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using MySql.Data.MySqlClient;
using UnityEngine.UI;


public class dbControl : MonoBehaviour {

    string database_connection = "server" + "uid=;" + "pwd=;" + "database=;";
    public Text nick;
    public Text password;
    public GameObject menu;


    public void connect()
    {
        MySqlConnection connection = new MySqlConnection(database_connection);
        connection.Open();

        connection->query("SELECT * FROM login WHERE nick='nick' AND password='password'");
        if (connection->query("SELECT * FROM login WHERE nick='nick' AND     password='password'")->num_rows > 0)
        {
            menu.SetActive(true);
            connection->Close();
        }

    }

}

Tak wygląda skrypt, który miał połączyć się do bazy i wysłać zapytanie o spójności wpisanego nicku i hasła.

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Errory:

 

Assets/dbControl.cs(18,9): error CS0012: The type `System.Data.Common.DbConnection' is defined in an assembly that is not referenced. Consider adding a reference to assembly `System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

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Assets/dbControl.cs(21,19): error CS0214: Pointers and fixed size buffers may only be used in an unsafe context
 

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Assets/dbControl.cs(21,19): error CS0193: The * or -> operator must be applied to a pointer

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Assets/dbControl.cs(22,23): error CS0214: Pointers and fixed size buffers may only be used in an unsafe context

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Assets/dbControl.cs(22,23): error CS0193: The * or -> operator must be applied to a pointer

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Assets/dbControl.cs(25,23): error CS0214: Pointers and fixed size buffers may only be used in an unsafe context

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Assets/dbControl.cs(25,23): error CS0193: The * or -> operator must be applied to a pointer

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