ASP.NET ADO.NET数据访问技术(一使用Command对象的 增删查改 )

使用Command对象进行数据库操作
一、插入数据

//引用数据库访问名称空间
using System.Data.SqlClient;
using System.Configuration;

string sqlconnstr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
  SqlConnection sqlconn = new SqlConnection(sqlconnstr);
  //建立Command对象
  SqlCommand sqlcommand = new SqlCommand();
  sqlcommand.Connection = sqlconn;
  //把SQL语句赋给Command对象
  sqlcommand.CommandText = "insert into student(No,Name,Sex,birthday,Adress,Photo)values (@No,@Name,@Sex,@birthday,@Adress,@Photo)";
  sqlcommand.Parameters.AddWithValue("@No",TextBox1.Text);    
  sqlcommand.Parameters.AddWithValue("@Name",TextBox2.Text);    
  sqlcommand.Parameters.AddWithValue("@Sex",DropDownList1.Text);    
  sqlcommand.Parameters.AddWithValue("@birthday",TextBox3.Text);    
  sqlcommand.Parameters.AddWithValue("@Adress",TextBox4.Text);    
  sqlcommand.Parameters.AddWithValue("@Photo",FileUpload1.FileName);    
  try
  {
       //打开连接
       sqlconn.Open();
       //执行SQL命令
       sqlcommand.ExecuteNonQuery();
       //把学生的照片上传到网站的images文件夹中
     if (FileUpload1.HasFile == true)
       {
           FileUpload1.SaveAs(Server.MapPath(("~/image/") + FileUpload1.FileName));
       }
       Label1.Text = "成功增加记录";
  }
  catch (Exception ex)
  {
       Label1.Text = "错误原因："+ ex.Message;
  }
  finally
  {
       sqlcommand = null;
       sqlconn.Close();
       sqlconn = null;
  }

二、删除操作

//引用数据库访问名称空间
using System.Data.SqlClient;
using System.Configuration;

int intDeleteCount;
string sqlconnstr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
SqlConnection sqlconn = new SqlConnection(sqlconnstr);
//建立Command对象
SqlCommand sqlcommand = new SqlCommand();
//给Command对象的Connection和CommandText属性赋值
sqlcommand.Connection = sqlconn;
sqlcommand.CommandText = "delete from student where no=@no";
sqlcommand.Parameters.AddWithValue("@no", TextBox1.Text);
try
{
    sqlconn.Open();
    intDeleteCount = sqlcommand.ExecuteNonQuery();
    if (intDeleteCount > 0)
        Label1.Text = "成功删除记录";
    else
        Label1.Text = "该记录不存在";
}
catch (Exception ex)
{
    Label1.Text = "错误原因：" + ex.Message;
}
finally
{
    sqlcommand = null;
    sqlconn.Close();
    sqlconn = null;
}

三、查询操作

//引用数据库访问名称空间
using System.Data.SqlClient;
using System.Configuration;

string sqlconnstr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
SqlConnection sqlconn = new SqlConnection(sqlconnstr);
//建立Command对象
SqlCommand sqlcommand = new SqlCommand();
//给sqlcommand的Connection属性赋值
sqlcommand.Connection = sqlconn;
//打开连接
sqlconn.Open();
//SQL命令赋值
sqlcommand.CommandText = "select * from student";
//建立DataReader对象，并返回查询结果
SqlDataReader sqldatareader = sqlcommand.ExecuteReader();
//逐行遍历查询结果
while (sqldatareader.Read())
{
    Label1.Text += sqldatareader.GetString(0) + "  ";
    Label1.Text += sqldatareader.GetString(1) + "  ";
    Label1.Text += sqldatareader.GetString(2) + "  ";
    Label1.Text += sqldatareader.GetDateTime(3) + "  ";
    Label1.Text += sqldatareader.GetString(4) + "  ";
    Label1.Text += sqldatareader.GetString(5) + "&nbsp;&nbsp;<br>";
};
sqlcommand = null;
sqlconn.Close();
sqlconn = null;

四、更新操作
此处一般运用数据库的存储过程进行修改

/* 修改数据存储过程 
CREATE  PROCEDURE update_student
(
   @No nvarchar(10),
   @Name nvarchar(50),
   @Sex nvarchar(2),
   @birthday datetime,
   @adress nvarchar(50),
   @Photo nvarchar(50)
) 
 AS 
   UPDATE student SET  No=@No,Name=@Name,Sex=@Sex,birthday=@birthday,adress=@adress,Photo=@Photo WHERE No=@No
   RETURN 0  
*/  


//引用数据库访问名称空间
using System.Data.SqlClient;
using System.Configuration;

int intUpdateCount;
string sqlconnstr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
SqlConnection sqlconn = new SqlConnection(sqlconnstr);
//建立Command对象
SqlCommand sqlcommand = new SqlCommand();
sqlcommand.Connection = sqlconn;
//把存储过程名称赋给Command对象的CommandText属性
sqlcommand.CommandText = "update_student";

//说明命令类型为存储过程
sqlcommand.CommandType = CommandType.StoredProcedure;

sqlcommand.Parameters.AddWithValue("@No", TextBox1.Text);
sqlcommand.Parameters.AddWithValue("@Name", TextBox2.Text);
sqlcommand.Parameters.AddWithValue("@Sex", DropDownList1.Text);
sqlcommand.Parameters.AddWithValue("@birthday", TextBox3.Text);
sqlcommand.Parameters.AddWithValue("@Adress", TextBox4.Text);
sqlcommand.Parameters.AddWithValue("@Photo", FileUpload1.FileName);
try
{
    //打开连接
    sqlconn.Open();
    //执行SQL命令
    intUpdateCount = sqlcommand.ExecuteNonQuery();
    //把学生的照片上传到网站的image文件夹中
    if (FileUpload1.HasFile == true)
    {
        FileUpload1.SaveAs(Server.MapPath(("~/images/") + FileUpload1.FileName));
    }
    if (intUpdateCount > 0)
        Label1.Text = "成功修改记录";
    else
        Label1.Text = "该记录不存在";
}
catch (Exception ex)
{
    Label1.Text = "错误原因：" + ex.Message;
}
finally
{
    sqlcommand = null;
    sqlconn.Close();
    sqlconn = null;
}