SQLiteHelper

// 写得不好，放在这里只是保存代码和自用
// 在Unity中使用时，需要先在Plugins文件夹中准备好相应的文件
using System;
using System.IO;
using Mono.Data.Sqlite;

public static class SQLiteHelper
{
    // 在Connect和CreateDB用到的路径字符串中，一律使用“\”而不是“/”
    public static bool Connect(out SqliteConnection connection, out SqliteCommand command, string pathAndFileName, bool allowCreate = false)
    {
        if (!allowCreate && !File.Exists(pathAndFileName))
        { connection = null; command = null; return false; }

        connection = new SqliteConnection();
        connection.ConnectionString = "data source = " + pathAndFileName;
        command = new SqliteCommand();
        command.Connection = connection;
        try
        { connection.Open(); return true; }
        catch (Exception)
        { DisconnectAndClear(ref connection, ref command); return false; }
    }

    public static void DisconnectAndClear(ref SqliteConnection connection, ref SqliteCommand command)
    {
        if (command != null)
        { command.Cancel(); command.Dispose(); }
        if (connection != null)
        { connection.Dispose(); }
        command = null; connection = null;
    }

    public static SqliteDataReader ExecuteQuery(SqliteCommand command, string queryString)
    {
        command.CommandText = queryString;
        return command.ExecuteReader();
    }

    public static bool CreateDB(string path, string fileName)
    {
        if (!Directory.Exists(path))
            return false;
        if (File.Exists(path + "\\" + fileName))
            return false;
        // ---------------- ---------------- ----------------
        SqliteConnection connection;
        SqliteCommand command;
        if (Connect(out connection, out command, path + "\\" + fileName, true))
        {
            DisconnectAndClear(ref connection, ref command);
            return true;
        }
        else
            return false;
    }
}