DaniWeb Forum Index > Software Development > C#

How to check if an ID exist in database

Please support our C# advertiser: Intel Parallel Studio Home

•

Join Date: Oct 2009

Posts: 1

Reputation: sara455 is an unknown quantity at this point

Solved Threads: 0

sara455

Offline

Newbie Poster

How to check if an ID exist in database

Oct 22nd, 2009

Im doing an application n c# and using Ms Access 2003. i want to check whether a product id already exist in the database. Below is part of my code

 Help with Code Tags 
 C# Syntax (Toggle Plain Text) 
string sql;
            OleDbCommand cmd;
            OleDbDataReader rdr;
 
 
            mDB.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0; Data source=" + Path.Combine(Application.StartupPath, "..\\..\\Company.mdb");
            mDB.Open();
            sql = "Select COUNT (*) ProductID FROM Product";
 
 
 
            cmd = new OleDbCommand(sql, mDB);
 
            rdr = cmd.ExecuteReader();
            if (txtProductID.Text == (string)rdr["ProductID"] )
            {
 
                MessageBox.Show("ID exixst");
 
            }
            else
            {
                return;
 
            }
string sql;
            OleDbCommand cmd;
            OleDbDataReader rdr;
           

            mDB.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0; Data source=" + Path.Combine(Application.StartupPath, "..\\..\\Company.mdb");
            mDB.Open();
            sql = "Select COUNT (*) ProductID FROM Product";



            cmd = new OleDbCommand(sql, mDB);

            rdr = cmd.ExecuteReader();
            if (txtProductID.Text == (string)rdr["ProductID"] )
            {

                MessageBox.Show("ID exixst");

            }
            else
            {
                return;

            }

•

Join Date: Oct 2009

Posts: 12

Reputation: DanielGreen is an unknown quantity at this point

Solved Threads: 2

DanielGreen DanielGreen is offline

Offline

Newbie Poster

Oct 22nd, 2009

Hi!

One possibility is, that you do an other sql-statement where you try to select the desired ProduktID:

 Help with Code Tags 
 C# Syntax (Toggle Plain Text) 
string sqlString = "Select ProductID FROM Product where ProductID="+txtProductID.Text;
OleDbCommand dbCmd = new OleDbCommand(sqlString, mDB);
mDB.Open();
OleDbDataReader reader = dbCmd.ExecuteReader();
if (reader.Read())
{
	MessageBox.Show("ID exixst");
}
else
{
  // do something else here
}
string sqlString = "Select ProductID FROM Product where ProductID="+txtProductID.Text;
OleDbCommand dbCmd = new OleDbCommand(sqlString, mDB);
mDB.Open();
OleDbDataReader reader = dbCmd.ExecuteReader();
if (reader.Read())
{
	MessageBox.Show("ID exixst");
}
else
{
  // do something else here
}