C#操纵大量数据表的一种方法菜鸟经验谈

问题描述：一个数据库中的某张表A有5，6万条记录。我们要对该表的每条记录做相同的处理，并将处理结果保存到表B。
这时我们不能采用SqlDataReader读一条记录，处理，储存到表B的方案。因为sqldatareader对数据库连接具有独占性，所以我们就不能储存记录到表B了。还有一种方案是可行的，就是在内存中采用datatable数据结构映射一张A的虚表A‘，这种方法固然可行。但是这样做无疑是耗内存的。于是我们采取以下方案（这里的表Article就对应于上文抽象模型中的表A）
DataBaseManipulation dbm=new DataBaseManipulation();
string conStr = "server=(local);database=ArticleCollection;uid=sa;pwd=123456";
string table = "Article";
SqlConnection conn = new SqlConnection(conStr);//建立连接

int ArticleLastIndex = dbm.GetTableLastIndex(table, conn, "ArticleId");
int lastindex = 0;

while (lastindex < ArticleLastIndex)
{
string select = string.Format("select top 100 ArticleId,AuthorString,WorkPlaceString From Article Where ArticleId>{0} ORDER BY ArticleId", lastindex);
SqlDataAdapter adapter = new SqlDataAdapter(select, conn);
DataTable dt = new DataTable();
adapter.Fill(dt);

int lastAuthorIndex = dbm.GetTableLastIndex("Author", conn, "AuthorId");

for (int i = 0; i < dt.Rows.Count; i++)
{
//处理每条记录
.........................................................
//将每条记录处理的结果保存至Author表中（Author表相当于上文抽象建模中的表B）

}
lastindex = int.Parse(dt.Rows[dt.Rows.Count - 1]["ArticleId"].ToString());
}
//数据库操纵的类

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient;

namespace CreateAuthorEntity
{
class DataBaseManipulation
{
public int GetDataBaseTableCount(string table, SqlConnection conn, string des)
{
string findCount = string.Format("SELECT COUNT({0}) FROM {1}", des, table);
conn.Open();
SqlCommand command = new SqlCommand(findCount, conn);
SqlDataReader reader = command.ExecuteReader();
reader.Read();
int count = reader.GetInt32(0);
reader.Close();
conn.Close();
return count;

}
public int GetTableLastIndex(string table, SqlConnection conn, string des)
{
int lastIndex;
string findLastIndex = string.Format("SELECT MAX({0}),COUNT({0}) FROM {1}", des, table);
conn.Open();
SqlCommand command = new SqlCommand(findLastIndex, conn);
SqlDataReader reader = command.ExecuteReader();
reader.Read();
if (reader.GetInt32(1) == 0)
{
lastIndex = 0;
}
else
{
lastIndex = reader.GetInt32(0);
}
reader.Close();
conn.Close();
return lastIndex;

}
}
}