Berkeley DB 基本使用.

最近在写蜘蛛。需要一张庞大的url表来记录各种url被线程的读取状况，因此需要连续的请求，以及多线程的并发操作等。
很显然，sqlserver并不能完全的满足需求。
推荐一下Berkeley DB
Berkeley DB相当于存储于本地硬盘的一个大的Hash表，由Key,Value构成.

需要下载的相关内容
Berkeley DB 4.5.20
Berkeley DB for .NET 0.95


基本操作
 // 添加数据到DBD数据库
        public  bool Add(string key,string obj)
        {
            string DbPath = @"e:\search\data\data.db";
            Db db = new Db(DbCreateFlags.None);
            DbEntry wKey = DbEntry.InOut(Encoding.UTF8.GetBytes(key));
            DbEntry wData = DbEntry.InOut(Encoding.UTF8.GetBytes(obj));
            DbFile dbf = db.Open(null, DbPath, null, BerkeleyDb.DbType.BTree, Db.OpenFlags.Create, 0);
            WriteStatus wStatus = dbf.Put(null, ref wKey, ref wData);
            dbf.Sync();
            db.Close();
            if (wStatus == WriteStatus.Success)
            {
                return true;
            }
            else
            {
                return false;
            }

        }

        // 根据key返回值
        public string GetVal(string key)
        {
            string result = string.Empty;
            DbEntry rData = DbEntry.Out(new byte[2048]);
            DbEntry rKey = DbEntry.InOut(Encoding.UTF8.GetBytes(key));
            Db db = new Db(DbCreateFlags.None);
            DbFile dbf = db.Open(null, DbPath, null, BerkeleyDb.DbType.BTree, Db.OpenFlags.Create, 0);
            ReadStatus rStatus = dbf.Get(null, ref rKey, ref rData, DbFile.ReadFlags.None);
            db.Close();
            if (rStatus == ReadStatus.Success)
            {
                result = Encoding.UTF8.GetString(rData.Buffer, 0, rData.Size);
            }
            return result;
        }