求~~~通过SQLDataReader读取数据的过程

2025-03-15 16:05:07
推荐回答(2个)
回答1:

//...前面省略
using System.Data.SqlClient; //1:引入命名空间

namespace Test
{
public partial class Form1 : Form
{
static string conStr = "server=.; database = myqq; uid=sa; pwd=0000;"; //2: 定义连接字符串
SqlConnection con = new SqlConnection(conStr); //3: 定义数据库连接对象

public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
string sql = "select * from Users"; //要查询的sql语句
SqlCommand cmd = new SqlCommand(sql, con); //4:创建sqlcommand对象, 执行sql语句
con.Open(); //5: 打开数据库连接
SqlDataReader dr = cmd.ExecuteReader(); //6: 执行sql语句并返回 sqldatareader对象 <相当赋值>
while (dr.Read()) //7:利用sqldatareader读取数据
{
MessageBox.Show("姓名是:"+dr["Uname"].ToString()); //只是举了一个例子
}
dr.Close(); //8:关闭sqldatareader
con.Close(); //9:关闭数据库连接

// 利用sqldatareader读取数据的时候,数据连接必须处于打开状态; 读取方式是 一行一行向前读取

}
}
}

回答2:

public void testReader(){

SqlConnection conn=new SqlConnection();
conn.ConnectionString="server=127.0.0.1;
initial catalog=Stu_xxx;user id=sa;password=sa ";
SqlCommand cmd=new SqlCommand ();
cmd.Connection=conn;
cmd.CommandText="select * from students where sname like '张%'";
conn.Open();

SqlDataReader sdr=cmd.ExecuteReader();

while(sdr.Read())
msg.Text+=“学号:”+sdr[“sid”].ToString()+
“姓名:”+sdr[“sname”].ToString()+
“生日:” +sdr[“sbirthday”].ToString()+”
”;

conn.Close();
}

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