一、實驗目的

掌握ADO .NET數據離線與在線訪問模型；

掌握應用LINQ進行數據查詢；

二、實驗內容

基于ADO.NET技術進行數據操作

已提供一個控制臺程序的框架。附件中提供了各種格式的Northwind數據庫。

參考案例程序，連接上數據庫，進行各種操作，補全該程序。

一些可用的SQL語句：

select * from 客戶 where 城市='南京'//找到所有位于南京的客戶

select count(*) from 客戶 where 城市='南京'//統計南京客戶的數量

update 客戶 set 城市='天津' where 客戶ID='ALFKI'//更新客戶信息，若滿足條件，就將“城市”字段改為天津

可自由選擇所查詢的數據庫表和參數。注意，SQL中字符串需加單引號。

class Test{static string _mdbFile = "D:/Northwind.mdb";static OleDbConnection _connection;static OleDbDataAdapter _adapter;static DataSet _dataset;public static void Main(string[] argv){while (true){int index = 1;Console.WriteLine("=====Menu=====");Console.WriteLine(index++ + ". 連接數據庫");Console.WriteLine(index++ + ". 查詢數據行");Console.WriteLine(index++ + ". 數據統計");Console.WriteLine(index++ + ". 更新數據庫");Console.WriteLine(index++ + ". 數據庫離線查詢");Console.WriteLine(index++ + ". 離線LINQ查詢");Console.WriteLine(index++ + ". 斷開數據庫");Console.WriteLine(index++ + ". 退出");Console.WriteLine("=====End======");Console.Write("請選擇一個操作：");string input = Console.ReadLine();int choice;bool isDigit = int.TryParse(input, out choice);if (!isDigit || choice >= index || choice < 1){Console.WriteLine("錯誤選項");}if (choice == index - 1)break;switch (choice){case 1:ConnectToDB();break;case 2:QueryWithReader();break;case 3:QueryScalar();break;case 4:UpdateOnLine();break;case 5:QueryOffLine();break;case 6:LINQQuery();break;case 7:CloseDB();break;}Console.WriteLine();}}public static bool IsConnected(){if (_connection == null || _connection.State != ConnectionState.Open){Console.WriteLine("數據庫未連接");return false;}return true;}public static void ConnectToDB(){string connString = @"Provider=Microsoft.ACE.OLEDB.12.0; Data Source=" + _mdbFile;_connection = new OleDbConnection(connString);//補全}public static void QueryWithReader(){if (!IsConnected())return;var command = _connection.CreateCommand();//補全}public static void QueryScalar(){}public static void UpdateOnLine(){}public static void QueryOffLine(){}public static void LINQQuery(){}public static void CloseDB(){}}

源代碼

using System; using System.Collections.Generic; using System.Data; using System.Data.OleDb; using System.Linq; using System.Text; using System.Threading.Tasks;namespace Homework12 {class Test{static string _mdbFile = "E:\\School Life\\University\\Study\\計算機\\程序語言\\C#\\第十三次課0529\\Northwind\\Northwind.mdb";static OleDbConnection _connection;static OleDbDataAdapter _adapter;static DataSet _dataset;public static void Main(string[] argv){while (true){int index = 1;Console.WriteLine("=====Menu=====");Console.WriteLine(index++ + ". 連接數據庫");Console.WriteLine(index++ + ". 查詢數據行");Console.WriteLine(index++ + ". 數據統計");Console.WriteLine(index++ + ". 更新數據庫");Console.WriteLine(index++ + ". 數據庫離線查詢");Console.WriteLine(index++ + ". 離線LINQ查詢");Console.WriteLine(index++ + ". 斷開數據庫");Console.WriteLine(index++ + ". 退出");Console.WriteLine("=====End======");Console.Write("請選擇一個操作：");string input = Console.ReadLine();int choice;bool isDigit = int.TryParse(input, out choice);if (!isDigit || choice >= index || choice < 1){Console.WriteLine("錯誤選項");}if (choice == index - 1)break;switch (choice){case 1:ConnectToDB();break;case 2:QueryWithReader();break;case 3:QueryScalar();break;case 4:UpdateOnLine();break;case 5:QueryOffLine();break;case 6:LINQQuery();break;case 7:CloseDB();break;}Console.WriteLine();}}public static bool IsConnected(){if (_connection == null || _connection.State != ConnectionState.Open){Console.WriteLine("數據庫未連接");return false;}return true;}public static void ConnectToDB(){string connString = @"Provider=Microsoft.ACE.OLEDB.12.0; Data Source=" + _mdbFile;_connection = new OleDbConnection(connString);//補全try{_connection.Open();Console.WriteLine("數數據庫連接成功：" + _mdbFile + " is " + _connection.State);}catch(Exception e){Console.WriteLine(e.Message);_connection.Close();}finally {}}public static void QueryWithReader(){if (!IsConnected())return;var command = _connection.CreateCommand();//補全command.CommandText = "select * from 客戶 where 城市='南京'";OleDbDataReader reader = command.ExecuteReader();while (reader.Read()){Console.WriteLine(reader[0].ToString());}reader.Close();}public static void QueryScalar(){if (!IsConnected())return;var command = _connection.CreateCommand();command.CommandText = "select count(*) from 客戶 where 城市='南京'";int count = (int)command.ExecuteScalar();Console.WriteLine("記錄總數："+count);}public static void UpdateOnLine(){if (!IsConnected())return;var command = _connection.CreateCommand();command.CommandText = "update 客戶 set 城市='天津' where 客戶ID='ALFKI'";int count = (int)command.ExecuteNonQuery();Console.WriteLine("更新 " + count + " 行");}public static void QueryOffLine(){if (!IsConnected())return;var command = _connection.CreateCommand();command.CommandText = "select * from 客戶";_dataset = new DataSet();DataTable dt1 = new DataTable("Scene");_dataset.Tables.Add(dt1);_adapter = new OleDbDataAdapter(command);_adapter.Fill(dt1);var query = from x in dt1.AsEnumerable()select x;foreach (DataColumn column in dt1.Columns)Console.Write(column.ColumnName+"\t");Console.WriteLine();foreach (var row in query){foreach (DataColumn column in dt1.Columns)Console.Write(row[column.ColumnName] + "\t");Console.WriteLine();}}public static void LINQQuery(){if (!IsConnected())return;var command = _connection.CreateCommand();command.CommandText = "select * from 客戶 where 城市='南京'";_dataset = new DataSet();DataTable dt1 = new DataTable("Scene");_dataset.Tables.Add(dt1);_adapter = new OleDbDataAdapter(command);_adapter.Fill(dt1);var query = from x in dt1.AsEnumerable()where (string)x["城市"] == "南京"select x;foreach (DataColumn column in dt1.Columns)Console.Write(column.ColumnName + "\t");Console.WriteLine();foreach (var row in query){foreach (DataColumn column in dt1.Columns)Console.Write(row[column.ColumnName] + "\t");Console.WriteLine();}}public static void CloseDB(){if (!IsConnected())return;_connection.Close();Console.WriteLine("數數據庫關閉成功：" + _mdbFile + " is " + _connection.State);}} }

運行結果

三、實驗心得與體會

掌握ADO .NET數據離線與在線訪問模型；

掌握應用LINQ進行數據查詢；

參考文章

?https://blog.csdn.net/zac_sian/article/details/51161563

https://www.runoob.com/csharp/csharp-for-loop.html

https://docs.microsoft.com/zh-cn/dotnet/api/system.data.datarow?view=netframework-4.8

https://docs.microsoft.com/zh-cn/dotnet/api/system.data.oledb.oledbdataadapter?view=dotnet-plat-ext-3.1

總結

以上是生活随笔為你收集整理的C#——《C#语言程序设计》实验报告——数据库编程——基于ADO.NET技术的数据库操作DEMO的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。