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  • 数据库简单增删改查

    namespace 数据库增删改查
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }
    
            private void button1_Click(object sender, EventArgs e) //登陆(查询)
            {
                string user = textBox2.Text;
                string password = textBox3.Text;
    
                SqlConnection coon = new SqlConnection("server=.;database=enter;user=sa;pwd=123"); //连接数据库
                coon.Open();//打开数据库
                SqlCommand cmd = coon.CreateCommand();//执行查询语句
                cmd.CommandText = "select * from enters where username='"+user+"' and userpass='"+password+"'"; //进行匹配
                SqlDataReader dr = cmd.ExecuteReader();//执行查询,将结果反馈给dr
                if (dr.Read())
                {
                    MessageBox.Show("登陆成功");
                }
                else
                {
                    MessageBox.Show("登陆失败");
                }
                coon.Close();
    
            }
    
            private void button3_Click(object sender, EventArgs e) //添加
            {
                string user = textBox2.Text;
                string password = textBox3.Text;
                SqlConnection coon = new SqlConnection("server=.;database=enter;user=sa;pwd=123");
                coon.Open();
                SqlCommand cmd = coon.CreateCommand();
                cmd.CommandText = "insert into enters values('"+user+"','"+password+"')";
                int count = cmd.ExecuteNonQuery();//增删改都用这个
                if(count>0)
                {
                    MessageBox.Show("添加成功");
                }
                coon.Close();
            }
    
            private void button2_Click(object sender, EventArgs e) //修改
            {
                string code = textBox1.Text;
                string user = textBox2.Text;
                string password = textBox3.Text;
                SqlConnection coon = new SqlConnection("server=.;database=enter;user=sa;pwd=123");
                coon.Open();
                SqlCommand cmd = coon.CreateCommand();
                cmd.CommandText = "update enters set username='"+user+"' , userpass='"+password+"' where code="+code;
                int count = cmd.ExecuteNonQuery();
                if(count>0)
                {
                    MessageBox.Show("修改成功");
                }
                else
                {
                    MessageBox.Show("修改失败!");
                }
                coon.Close();
            }
    
            private void button4_Click(object sender, EventArgs e) //删除
            {
                string code = textBox1.Text;
                SqlConnection coon = new SqlConnection("server=.;database=enter;user=sa;pwd=123");
                coon.Open();
                SqlCommand cmd = coon.CreateCommand();
                cmd.CommandText = "delete from enters where code="+code;
                cmd.ExecuteNonQuery();
                coon.Close();
            }
        }
    }
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  • 原文地址:https://www.cnblogs.com/lk-kk/p/4544886.html
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