program.cs

讲述如何使用c#访问关系数据库

#region Using directives

using System;
using System.Data;            // Use ADO.NET namespace
using System.Data.SqlClient;  // Use SQL Server data provider namespace
using System.Collections.Generic;
using System.Text;

#endregion

namespace FindingData
{
	class Program
	{
		static void Main(string[] args)
		{
			// Specify SQL Server-specific connection string
			SqlConnection thisConnection = new SqlConnection(
				 @"Server=(local)\sqlexpress;Integrated Security=True;" +
				 "Database=northwind");

			// Create DataAdapter object for update and other operations
			SqlDataAdapter thisAdapter = new SqlDataAdapter(
				 "SELECT CustomerID, CompanyName FROM Customers", thisConnection);
			// Create CommandBuilder object to build SQL commands
			SqlCommandBuilder thisBuilder = new SqlCommandBuilder(thisAdapter);

			// Create DataSet to contain related data tables, rows, and columns
			DataSet thisDataSet = new DataSet();

			// Fill DataSet using query defined previously for DataAdapter
			thisAdapter.Fill(thisDataSet, "Customers");

			Console.WriteLine("# rows before change: {0}",
				 thisDataSet.Tables["Customers"].Rows.Count);

			// Set up keys object for defining primary key
			DataColumn[] keys = new DataColumn[1];
			keys[0] = thisDataSet.Tables["Customers"].Columns["CustomerID"];
			thisDataSet.Tables["Customers"].PrimaryKey = keys;

			DataRow findRow = thisDataSet.Tables["Customers"].Rows.Find("ZACZI");

			if (findRow == null)
			{
				Console.WriteLine("ZACZI not found, will add to Customers table");

				DataRow thisRow = thisDataSet.Tables["Customers"].NewRow();
				thisRow["CustomerID"] = "ZACZI";
				thisRow["CompanyName"] = "Zachary Zithers Ltd.";
				thisDataSet.Tables["Customers"].Rows.Add(thisRow);
				if ((findRow =
					 thisDataSet.Tables["Customers"].Rows.Find("ZACZI")) != null)
				{
					Console.WriteLine("ZACZI successfully added to Customers table");
				}
			}
			else
			{
				Console.WriteLine("ZACZI already present in database");
			}

			thisAdapter.Update(thisDataSet, "Customers");

			Console.WriteLine("# rows after change: {0}",
			thisDataSet.Tables["Customers"].Rows.Count);

			thisConnection.Close();
			Console.Write("Program finished, press Enter/Return to continue:");
			Console.ReadLine();
		}
	}
}