Unity SQLite本地数据库

Question

I am making a small game in Unity and I'm in need of a database. I tried using SQLite database because that seemed to be recommended by the web.

Now I'm having troubles with actually connecting to the local database via c#.

I implemented the Data in SQLite .dll's. I am trying to get 1 name from the database that I created using SQLite developer.

Below is my DataConnection class, which I use to connect to the database.

using UnityEngine;
using System.Collections;
using System.Data;
using Mono.Data.SqliteClient;

public class Dataconnection : MonoBehaviour {

private string _constr = @"Data Source=C:\Program Files (x86)\SharpPlus\SqliteDev\GameDatabase.db;Version=3;";
private IDbConnection _dbc;
private IDbCommand _dbcm;
private IDataReader _dbr;


public Dataconnection()
{

}

public Dataconnection(string constring)
{
        _constr = constring;
}

public string ExcecuteQuery(string SQL)
{
    string output = "";

    try
    {
        _dbc = new SqliteConnection(_constr);
        _dbc.Open();
        _dbcm = _dbc.CreateCommand();
        _dbcm.CommandText = SQL;
        _dbr = _dbcm.ExecuteReader();
    }
    catch
    {

    }

    while (_dbr.Read())
    {
        output = _dbr.GetString(0);
    }

    _dbc.Close();

    return output;
}   
}

Then I call the following method from another class:

datacon.ExcecuteQuery("SELECT name FROM employee WHERE empid = 1;");

I get the following errors when running the code:

So I'm guessing it has something to do with a 32/64 -bit mismatch or is there something wrong with creating an instance of a script like this?:

private Dataconnection datacon;

void Start()
{
    datacon = new Dataconnection();
}

Happy to receive any help at all. I'm familiar with using database, just new to SQLite.

Answer 1

It says it cannot load the native sqlite.dll because you have there 64 bit version and it needs 32 bit

Place this in your app folder https://www.sqlite.org/2015/sqlite-dll-win32-x86-3081001.zip

Please fill that empty catch on line 38 with a throw;

as there is an exception hidden there which is the true cause of the null reference.

You could also post your connection string so I could make this answer better.

Answer 2

I got it working now. The problem was my that one of the SQLite .dll's was still 32bit. I did this tutorial over again and searched google for the 64bit .dll files and now it's working.