C# OleDbCommand 和 OleDbDataReader 使用小结

用代码直接说明好了.
using System.Data;
using System.Data.OleDb;
OleDbConnection thisConnection = new OleDbConnection(
      "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Server.MapPath("data.mdb"));//获取本地Access
//数据库路径
     thisConnection.Open();
     string strCom = "select * from account where uid = '" + strUid + "' and pwd = '" + strPwd + "'";
     OleDbCommand thisCommand = new OleDbCommand(strCom,thisConnection);
     thisCommand.ExecuteReader();  或者 thisCommand.ExecuteNonQuery();  
(这两句都可以执行sql语句)
thisConnection.Close();
将下划线部分替换为:
OleDbDataReader thisReader = thisCommand.ExecuteReader();
     if(thisReader.HasRows)
{
      thisReader.Read();
      string strLevel = thisReader["level"].ToString();
}
或者
if(thisReader.Read())
{
string strLevel = thisReader["level"].ToString();
}
OleDbDataReader 中的bool类型HasRows属性可以判断查询结果是否为空.
thisReader["列名"] 可显示查询出的该列数据.