调试易

namespace chengjiguanli
{
    public partial class Banjixinxi_xiugai : Form
    {
        SqlConnection conn = null;
        SqlCommand cmd = null;
        public Banjixinxi_xiugai()
        {
            InitializeComponent();
        }        private void button1_Click(object sender, EventArgs e)
        {
            string sjk = @"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\db.mdf;Integrated Security=True;User Instance=True";
            conn = new SqlConnection(sjk);
              
            if ((this.textBox2 .Text.Trim() == "") || (this.textBox3 .Text.Trim() == "") || this.textBox4 .Text.Trim() == "")
                MessageBox.Show("请输入完整的课程信息","提示");
            else
            {
                conn.Open();
                string sql = "select * from gerenxinxi where 学号<>'" + this.textBox1.Text  .ToString() + "' and 姓名='" + this.textBox2 .Text .ToString() + "'";
                cmd = new SqlCommand(sql, conn);
                
                if (null != cmd.ExecuteScalar())
                    MessageBox.Show("姓名发生重复", "提示");
                else
                {
                    string sql1 = "update gerenxinxi set 姓名='" + this.textBox2.Text.Trim() + "',性别='" + this.textBox3.Text.Trim() + "',班级='" + this.textBox4.Text.Trim() + "', 专业='" + this.textBox5.Text.Trim() + "',出生日期='" + this.textBox6.Text.Trim() + "',家庭住址='" + this.textBox7.Text.Trim() + "'" +
                        " where 学号='" + this.textBox1 .Text.Trim() + "'";
                    cmd = new SqlCommand(sql1, conn);
                    cmd.ExecuteNonQuery();
                    MessageBox.Show("学生信息修改成功", "提示");
                    this.Close();
                    
                }
                
                conn.Close();
               
            }        }        private void button2_Click(object sender, EventArgs e)
        {
            this.Close();        }
    }
}
修改完成后可以查询出来修改，关掉程序再打开程序依然可以查询到，但是过一段时间就查不到修改了。很奇怪。物理数据库一直没有变化。