Question

使用ADO执行SQL语句后，怎么输出

Answer 1

实例：
第一、查询数据：
string
MyConn="server=127.0.0.1;uid=user;pwd=123456;database=Northwind;Trusted_Connection=no";//定义数据库连接参数
SqlConnection
MyConnection=new SqlConnection(MyConn);//定义一个数据连接实例
SqlCommand MyCommand=new
SqlCommand("SELECT CategoryID, CategoryName, Description FROM
Categories",MyConnection); //定义一个数据库操作指令
SqlDataAdapter SelectAdapter=new
SqlDataAdapter();//定义一个数据适配器
SelectAdapter.SelectCommand=MyCommand;//定义数据适配器的操作指令
DataSet
MyDataSet=new
DataSet();//定义一个数据集
MyConnection.Open();//打开数据库连接
SelectAdapter.SelectCommand.ExecuteNonQuery();//执行数据库查询指令
MyConnection.Close();//关闭数据库
SelectAdapter.Fill(MyDataSet);//填充数据集
DataGrid1.DataSource=MyDataSet;
DataGrid1.DataBind();//将数据表格用数据集中的数据填充
第二、添加数据
string
MyConn="server=127.0.0.1;uid=user;pwd=123456;database=Northwind;Trusted_Connection=no";
SqlConnection
MyConnection=new SqlConnection(MyConn);
string MyInsert="insert into
Categories(CategoryName,
Description)values('"+Convert.ToString(TextBox2.Text)+"','"+Convert.ToString(TextBox3.Text)+"')";
SqlCommand
MyCommand=new
SqlCommand(MyInsert,MyConnection);
try//异常处理
{
MyConnection.Open();
MyCommand.ExecuteNonQuery();
MyConnection.Close();
}
catch(Exception
ex)
{
Console.WriteLine("{0} Exception caught.", ex);
}

第三、修改数据
string categoryName=TextBox2.Text;
string
categoryDescription=TextBox3.Text;
string
MyConn="server=127.0.0.1;uid=user;pwd=123456;database=Northwind;Trusted_Connection=no";
SqlConnection
MyConnection=new SqlConnection(MyConn);
string MyUpdate="Update Categories
set CategoryName='"+categoryName+"',Description='"+categoryDescription+"' where
CategoryID="+TextBox1.Text;
SqlCommand MyCommand=new
SqlCommand(MyUpdate,MyConnection);
try
{
MyConnection.Open();
MyCommand.ExecuteNonQuery();
MyConnection.Close();
TextBox1.Text="";
}
catch(Exception
ex)
{
Console.WriteLine("{0} Exception caught.", ex);
}

第四、删除数据
string
MyConn="server=127.0.0.1;uid=user;pwd=123456;database=Northwind;Trusted_Connection=no";
SqlConnection
MyConnection=new SqlConnection(MyConn);
string MyDelete="Delete from
Categories where CategoryID="+TextBox1.Text;
SqlCommand MyCommand=new
SqlCommand(MyDelete,MyConnection);
try
{
MyConnection.Open();
MyCommand.ExecuteNonQuery();
MyConnection.Close();
TextBox1.Text="";
}
catch(Exception
ex)
{
Console.WriteLine("{0} Exception caught.", ex);
}