关于ACCESS中的CreateTable

ACCESS数据库中我创建了一个表 用以下语句
string create = @"Create Table MusicInfo
                (
                    [FilePath] nvarchar(250) not null ,
                    [SongName] nvarchar(200) ,
                    [Artist] nvarchar(40) ,
                    [ext] nchar(10) ,
                    constraint [Pk_Path] primary key([FilePath])
                )    
            ";貌似创建出来的数据类型不对劲我在使用以下语句插入数据时，101个字符的一个字符串就说“字段太小而不能接受所要添加的数据的数量。试着插入或粘贴较少的数据。”OleDbCommand cmd = new OleDbCommand("insert into [MusicInfo] ( [FilePath] , [SongName],[Artist],[Ext]) values (@filepath,@songname,@artist,@ext)", Connection);
            OleDbParameter[] paras = new OleDbParameter[]
            {
                new OleDbParameter("@filepath",OleDbType.WChar,filepath.Length),
                new OleDbParameter("@songname",OleDbType.WChar,songname.Length),
                new OleDbParameter("@artist",OleDbType.WChar,artist.Length),
                new OleDbParameter("@ext",OleDbType.WChar,ext.Length)
            };            paras[0].Value = filepath;
            paras[1].Value = songname;
            paras[2].Value = artist;
            paras[3].Value = ext;
            cmd.Parameters.AddRange(paras);
            try
            {
                Connection.Open();
                cmd.ExecuteNonQuery();
            }
            finally
            {
                Connection.Close();
            }是不是ACCESS不支持nvarchar？