using UnityEngine;
using System.Collections;
using System;
using Mono.Data.Sqlite;
public class DbTool
{

    // Use this for initialization
    private SqliteConnection dbConnection;
    public SqliteCommand dbCommand;
    public SqliteDataReader reader;
    public static string dataBase = "ScoreDB.db";
    public static string connectionString = "";
    //创建 SingleObject 的一个对象
    private static DbTool instance = new DbTool();
   
   //获取唯一可用的对象
   public static DbTool getInstance()
   {
      return instance;
   }

    public void OpenDB(string database)
    {
        try
        {
            connectionString = "Data Source=" + Application.dataPath + "/" + database + ";";//Version=3
            dbConnection = new SqliteConnection(connectionString);
            dbConnection.Open();
            dbCommand = (SqliteCommand)dbConnection.CreateCommand();
            //Debug.Log("Connected to db");
            
        }
        catch (Exception e)
        {
            Debug.Log(e);
        }
    }

    public void CloseSqlConnection()
    {
        if (dbCommand != null)
        {
            dbCommand.Cancel();
        }
        dbCommand = null;

        if (reader != null)
        {
            reader.Close();
        }
        reader = null;

        if (dbConnection != null)
        {
            dbConnection.Close();
        }
        dbConnection = null;
        //Debug.Log("Disconnected from db.");
    }

    public SqliteDataReader ExecuteQuery(string sqlQuery)
    {
        try
        {
            //dbCommand = (SqliteCommand)dbConnection.CreateCommand();
            dbCommand.CommandText = sqlQuery;
            reader = dbCommand.ExecuteReader();
        }
        catch (Exception e)
        {
            Debug.Log(e);
        }
        return reader;
    }   
}