数据库连接 执行 select 语句

using System;
using System.Data.SqlClient;

namespace ConnectDB
{
class Program
{
static void Main(string[] args)
{
//指定数据库连接的SqlConnection.ConnectionString性质
//SqlConnection.ConnectionString详细详细参考
//MSDN网站：http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnection.connectionstring.aspx
string strConn = @"  server = (local);
integrated security = true;
database = 'northwind'  ";
/*
* 另一种指定数据库连接的SqlConnection.ConnectionString性质的方法是
* 使用SqlConnectionStringBuilder Class，
* 代码例子如下，
* 具体参考MSDN网站：http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnectionstringbuilder.aspx
* 和网站：http://blogs.msdn.com/b/cbowen/archive/2007/03/05/sqlconnectionstringbuilder.aspx
System.Data.SqlClient.SqlConnectionStringBuilder builder =
new System.Data.SqlClient.SqlConnectionStringBuilder();
builder["Data Source"] = "(local)";
builder["integrated Security"] = true;
builder["Initial Catalog"] = "AdventureWorks;NewValue=Bad";
//SqlConnectionStringBuilder.ConnectionString作为参数用创建连接实例
conn = new SqlConnection(builder.ConnectionString);
*/

SqlConnection conn = null;
SqlDataReader sqlReader = null;
try
{
//用strConn创建连接
conn = new SqlConnection(strConn);

conn.Open();//打开连接

//通过SqlConnection.CreateCommand()函数
//创建数据库命令SqlCommand
//SqlCommand的MSDN参考网站
//http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.aspx
SqlCommand sqlCmd = conn.CreateCommand();

//SqlCommand.CommandText指定数据库查询命令
sqlCmd.CommandText = "select * from dbo.Contacts";
//执行数据库查询命令，并把结果返回给SqlDataReader对象。
sqlReader = sqlCmd.ExecuteReader();
//通过while循环SqlDataReader.Read(),遍历读取的结果。
while (sqlReader.Read())
{
Console.WriteLine("{0},{1}",
sqlReader["ContactType"].ToString().PadRight(10),
sqlReader["CompanyName"].ToString().PadRight(15));
}
}
catch (Exception exp)
{
Console.WriteLine(exp.ToString());
}
finally
{
//别忘了要关闭连接哦！！
sqlReader.Close();
conn.Close();
}
}
}
}