Difficulty connecting to MySQL

Unity Engine
1

I’m running the latest Unity Free in on a Mac, OS 10.6.6. I’m following the instructions in this post:

Reading database and/or spreadsheets.

The CS script I’m trying to use is here:

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

public class DatabaseConnectionScript : MonoBehaviour {

	
	// Update is called once per frame
	void Update () {
	
	}
	    // Global variables
    private static IDbConnection dbConnection;
    
    // Initialisation
    public void Start() {
        openSqlConnection();
        Debug.Log("Database Script run.");
   }
    
    // On quit
    public void OnApplicationQuit() {
        closeSqlConnection();
    }
    
    // Connect to database
    private static void openSqlConnection() {
        string connectionString = "Server=localhost;" +
            "Database=Test01;" +
            "User ID=unity;" +
            "Password=password;" +
            "Pooling=false";
        dbConnection = new MySqlConnection(connectionString);
        dbConnection.Open();
        Debug.Log("Connected to database.");
    }
    
    // Disconnect from database
    private static void closeSqlConnection() {
        dbConnection.Close();
        dbConnection = null;
        Debug.Log("Disconnected from database.");
    }

    // MySQL Query
    public static void doQuery(string sqlQuery) {
        IDbCommand dbCommand = dbConnection.CreateCommand();
        dbCommand.CommandText = sqlQuery;
        IDataReader reader = dbCommand.ExecuteReader();
        reader.Close();
        reader = null;
        dbCommand.Dispose();
        dbCommand = null;
    }

}

I copied the two DLL files attached to the referenced post into the Assets folder of the project directory I’m working on.

When I try to run within the Unity environment just to see whether the code thus far is doing okay, I get these internal compiler errors:

I verified the subject MySQL database and user information exist on my Mac and I can log into the database normally.

Does anyone know what’s going wrong here?

Many thanks in advance!

2

The error message is not very informative but if you go to the player settings (menu: Edit > Project Settings > Player) and set the API compatibility level to 2.0, rather than 2.0 Subset then it should fix the problem. You may need to re-save the database script to make Unity register the change.

The System.Drawing library referenced in the error message is not applicable in Unity and is therefore only a placeholder implementation for the sake of other libraries that depend on it. When you have API compatibility set to Subset, Unity leaves out these “useless” libraries and other little-used ones as a way to save memory in the final build.

3

You’re the man! At first I thought it wasn’t going to work, but then I realized I hadn’t re-saved the script. Viola, I have connection.

Thank you!

4

A follow-up question: I intend for the final build to be deployed as a web app. Are there issues in that case with the app having access to the DLLs?

5

Wow… so I got exactly the same error as this guy…
I followed Andeee’s suggestion and I ended up getting nowhere…
So I did his advice backwards and ended up with the same error message twice…
i followed the advice again and lo and behold, now I only get the same error once again :stuck_out_tongue:

So, erm… how do I make that error go away?
Please, help…
Thanks