Access数据库sample.mdb只含一个表User，User结构如下：
id 自动编号
name 文本

C#程序如下：

using System;
using System.Data;
using System.Data.OleDb;

class Hello
{
    static void Main()
    {
        String connString = "Provider = Microsoft.Jet.OLEDB.4.0; Data Source = sample.mdb";
        String queryString = "SELECT * FROM [User]";
        using(OleDbConnection conn = new OleDbConnection( connString ))
        {
            OleDbDataAdapter mdbAdapter = new OleDbDataAdapter(queryString, conn);
            DataSet ds = new DataSet();
            conn.Open();
            mdbAdapter.Fill(ds, "User");
            DataRow dr = ds.Tables[ "User" ].NewRow();
            dr[ "name" ] = "k";
            ds.Tables[ "User" ].Rows.Add( dr );
            mdbAdapter.Update(ds, "User");        }
    }
}

异常信息：
未处理的异常:  System.InvalidOperationException: 当传递具有新行的 DataRow 集合时
，更新要求有效的 InsertCommand。
   在 System.(RowUpdatedEventArg
s rowUpdatedEvent, BatchCommandInfo[] batchCommands, Int32 commandCount)
   在 System.(RowUpdatedEventArgs rowU
pdatedEvent, BatchCommandInfo[] batchCommands, Int32 commandCount)
   在 System.(DataRow[] dataRows, DataTableMappi
ng tableMapping)
   在 System.(DataTable dataTable,
DataTableMapping tableMapping)
   在 System.(DataSet dataSet, String srcTable)
   在 Hello.Main()

别用user表

系统保留关键字

用users就可以了，你试试吧