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  • 3月9日 连接数据库(简单的增删改查)

    1

    1、增加:

    //增加
       private void button2_Click(object sender, EventArgs e)
       {
            string uname=textBox2.Text;
           string upass=textBox1.Text;

           SqlConnection conn = new SqlConnection("server=.;database=data1220;user=sa;pwd=sa");
           conn.Open();

           SqlCommand cmd = conn.CreateCommand();
           cmd.CommandText = "insert into table1 values('"+uname+"', '"+upass+"')";

           int count=cmd.ExecuteNonQuery();
           if (count > 0)
           {
               MessageBox.Show("增加成功");
           }
           else
           {
               MessageBox.Show("增加失败");
           }
           conn.Close();
       }

    执行结果:

    2       2.1

    2、删除

    //删除
           private void button4_Click(object sender, EventArgs e)
           {
               string code = textBox3.Text;

               SqlConnection conn = new SqlConnection("server=.;database=data1220;user=sa;pwd=sa");
               conn.Open();

               SqlCommand cmd = conn.CreateCommand();
               cmd.CommandText = "delete from table1 where code="+code;
               cmd.ExecuteNonQuery();
               conn.Close();
           }

    3、修改

    //修改
       private void button3_Click(object sender, EventArgs e)
       {
           string uname = textBox2.Text;
           string upass = textBox1.Text;
           string code = textBox3.Text;

           SqlConnection conn = new SqlConnection("server=.;database=data1220;user=sa;pwd=sa");
           conn.Open();

           SqlCommand cmd = conn.CreateCommand();
           cmd.CommandText = "update table1 set uname='"+uname+"',upass='"+upass+"'where code="+code;
           int count=cmd.ExecuteNonQuery();
           if (count > 0)
           {
               MessageBox.Show("修改成功");
           }
           else
           {
               MessageBox.Show("修改失败");
           }
           conn.Close();
       }

    4、查询

    //查询
           private void button1_Click(object sender, EventArgs e)
           {
               string uname=textBox2.Text;
               string upass=textBox1.Text;
               //连接数据库
               SqlConnection conn = new SqlConnection("server=.;database=data1220;user=sa;pwd=sa");
               conn.Open();
               //写执行语句
               SqlCommand cmd = conn.CreateCommand();  //通过conn创建SqlCommand对象
               cmd.CommandText = "select *from table1 where uname='"+uname+"' and upass='"+upass+"' ";
               SqlDataReader dr = cmd.ExecuteReader();  //执行查询,返回SqlDataReader对象

               if (dr.Read())
               {
                   MessageBox.Show("登陆成功");
               }
               else
               {
                   MessageBox.Show("登陆失败");
               }
               conn.Close();
           }

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  • 原文地址:https://www.cnblogs.com/tzq9308/p/4330287.html
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