How to check whether record exist in database or not

Question

1.00/5 (1 vote)

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I am checking

whether record exist in database or not

, but getting error as

Object reference not set to an instance of an object.

Actually what happen if record exist in databse it give message but when not exist it give error

What I have tried:

string time = DateTime.Now.Day.ToString();
      SqlConnection con5 = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);
      con5.Open();
      SqlCommand check_User_Name = new SqlCommand("select * from attendance where date= convert(varchar(11), getdate(), 105) and name=@name", con5);
      check_User_Name.Parameters.AddWithValue("@name", DropDownList1.Text);


      int UserExist = (int)check_User_Name.ExecuteScalar();

      if (UserExist > 0)
      {
          ShowPopUpMsg("Already Saved Today!!");
           DropDownList12.Enabled=false;
      }
      else
      {
          if (time == "12")
          {
              DropDownList12.Enabled = true;
          }
      }

      con5.Close();

Posted 11-Jan-18 17:41pm

ADI@345

Updated 11-Jan-18 19:00pm

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2 solutions

Solution 2

replacing * with count(1) would have fixed your issue

SQL

select count(1) from attendance where date= convert(varchar(11), getdate(), 105) and name=@name

Posted 11-Jan-18 19:00pm

Karthik_Mahalingam

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Altaf Ansari · Accepted Answer · 2018-01-11T18:14:00

Try This :

string query="select * from attendance where date= convert(varchar(11), getdate(), 105) and name=@name";

if(IsExist(query))
{
  // Recored Exist
}

 public bool IsExist(string Query)
        {
            bool check = false;
            using (cmd = new SqlCommand(Query, con))
            {
                con.Open();
                SqlDataReader sdr = cmd.ExecuteReader();
                if (sdr.HasRows)
                    check = true;
            }
            sdr.Close();
            con.Close();
            return check;

        }