OleDbDataReader、OleDbDataAdapter、DataSet 的使用方法

1、OleDbDataReader用于从数据库中读取数据，参考代码如下：

OleDbConnection conn = new OleDbConnection();
conn.ConnectionString = @"Provider=microsoft.ace.oledb.12.0;Data Source=|DataDirectory|湖州工厂故障现象及原因数据库.accdb;";
//查找故障现象表中有几行，用于下面定义数组大小用
OleDbCommand com = new OleDbCommand("SELECT COUNT(故障现象代码) AS NUM FROM 故障现象", conn);
conn.Open();
OleDbDataReader drNew = com.ExecuteReader();
drNew.Read();
int F_rows = int.Parse(drNew["NUM"].ToString());
drNew.Close();
conn.Close();

2、OleDbDataAdapter用于链接数据库，供DataSet使用，代码如下：

OleDbConnection conn = new OleDbConnection();
conn.ConnectionString = @"Provider=microsoft.ace.oledb.12.0;Data Source=|DataDirectory|湖州工厂故障现象及原因数据库.accdb;";
//获得故障现象表中的故障现象列表
OleDbDataAdapter Fname_Adapter = new OleDbDataAdapter("select 故障现象 from 故障现象", conn);
DataSet Fname_table = new DataSet();
Fname_Adapter.Fill(Fname_table, "故障现象");
int Fname_sum = Fname_table.Tables["故障现象"].Rows.Count;
string[] Fname = new string[Fname_sum];
for (int i = 0; i < Fname_table.Tables["故障现象"].Rows.Count;i++ )
{
    Fname[i] = (string)Fname_table.Tables["故障现象"].Rows[i]["故障现象"];
}
Fname_table.Dispose();
int[] F_times = new int[Fname_sum];
//获取查询记录中Fxxx的原始数据（这个数据有些是重复的，要对其进行处理）。
OleDbDataAdapter Fxxx_Adapter = new OleDbDataAdapter("select 故障现象 from 故障记录", conn);
DataSet Fxxx_table = new DataSet();
Fxxx_Adapter.Fill(Fxxx_table, "故障记录");
//string iii = (string)Fxxx_table.Tables["故障记录"].Rows[2]["故障现象"];
int F_contents_sum = Fxxx_table.Tables["故障记录"].Rows.Count;    //有几条故障记录
string[] F_contents = new string[F_contents_sum];
for (int j = 0; j < F_contents_sum; j++)
{
    F_contents[j] = (string)Fxxx_table.Tables["故障记录"].Rows[j]["故障现象"];
}
for (int j = 0; j < F_contents_sum; j++)
{
    for(int k=0;k<Fname_sum;k++)
    {
        if (F_contents[j] == Fname[k])
            F_times[k]++;
    }
}
Fxxx_table.Dispose();