Solved

How do I search in a database and get the values out?

Posted on 2009-05-03
4
162 Views
Last Modified: 2012-05-06
I have the code below. But I dont know how to get the info out.

Lets say I find the thing I was searching for.....how can I get it out? And will the return value be null if it doesnt exist?
Boolean flag = false;
        if (Page.IsValid)
        {
            String myConnectionString = "PROVIDER=Microsoft.Jet.OLEDB.4.0;Data Source= C:\\Documents and Settings\\MFL\\Dokumenter\\Visual Studio 2005\\WebSites\\WebSite\\WebSite\\Tenta1\\Nwind.mdb";
            OleDbConnection myConnection = new OleDbConnection(myConnectionString);
            string myInsertQuery = "SELECT * FROM Customers WHERE (CustomerID) ='" + SearchTextBox.Text + "'";          
            OleDbCommand myCommand = new OleDbCommand(myInsertQuery);
            myCommand.Connection = myConnection;
            myConnection.Open();
            myCommand.ExecuteNonQuery();
            myCommand.Connection.Close();

Open in new window

0
Comment
Question by:Mickeys
  • 2
  • 2
4 Comments
 
LVL 4

Accepted Solution

by:
cauos earned 500 total points
ID: 24289582
first of all let me clerify one thing for you:
ExecuteNonQuery(); used to executes a Transact-SQL statement against the connection and returns the number of rows affected by executing UPDATE, INSERT, or DELETE statements.
ExecuteReader():Executes the CommandText against the Connection, and returns an DbDataReader.by executing SELECT statement .
ExecuteScalar():Executes the query and returns the first column of the first row in the result set returned by the query. All other columns and rows are ignored.

and in your case you should use ExecuteReader() because you return one record from the reader.

in the example below i assume you have text boxs and you want to bind the data return to those textBoxs
Boolean flag = false;
        if (Page.IsValid)
        {
            String myConnectionString = "PROVIDER=Microsoft.Jet.OLEDB.4.0;Data Source= C:\\Documents and Settings\\MFL\\Dokumenter\\Visual Studio 2005\\WebSites\\WebSite\\WebSite\\Tenta1\\Nwind.mdb";
            OleDbConnection myConnection = new OleDbConnection(myConnectionString);
            string myInsertQuery = "SELECT * FROM Customers WHERE (CustomerID) ='" + SearchTextBox.Text + "'";          
            OleDbCommand myCommand = new OleDbCommand(myInsertQuery);
            myCommand.Connection = myConnection;
            myConnection.Open();
            OleDbDataReader rdr=myCommand.ExecuteReader();
rdr.Read();
txtBox1.Text=rdr[0].ToString();
......
....
txtBox2.Text=rdr[1].ToString();
txtBoxn.Text=rdr[n].ToString();
            myConnection.Close();

Open in new window

0
 

Author Comment

by:Mickeys
ID: 24289623
aha. but when I try to run the code I get
+            rdr[0]      'rdr[0]' threw an exception of type 'System.InvalidOperationException'      object {System.InvalidOperationException}

Is the statement wrong?
0
 

Author Comment

by:Mickeys
ID: 24289634
Hmm it seems if I write somehting that doesnt exicst i get that?? Could that be correct?
0
 
LVL 4

Expert Comment

by:cauos
ID: 24289723
if there is no record return this error will occur; and to be in the safe side use the line of code
 if (rdr.HasRows)
        {
        txtBox1.Text=rdr[0].ToString();
......
....
txtBox2.Text=rdr[1].ToString();
txtBoxn.Text=rdr[n].ToString();

        }
0

Featured Post

Master Your Team's Linux and Cloud Stack!

The average business loses $13.5M per year to ineffective training (per 1,000 employees). Keep ahead of the competition and combine in-person quality with online cost and flexibility by training with Linux Academy.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article describes how to use the timestamp of existing data in a database to allow Tableau to calculate the prior work day instead of relying on case statements or if statements to calculate the days of the week.
Performance in games development is paramount: every microsecond counts to be able to do everything in less than 33ms (aiming at 16ms). C# foreach statement is one of the worst performance killers, and here I explain why.
Although Jacob Bernoulli (1654-1705) has been credited as the creator of "Binomial Distribution Table", Gottfried Leibniz (1646-1716) did his dissertation on the subject in 1666; Leibniz you may recall is the co-inventor of "Calculus" and beat Isaac…
Nobody understands Phishing better than an anti-spam company. That’s why we are providing Phishing Awareness Training to our customers. According to a report by Verizon, only 3% of targeted users report malicious emails to management. With compan…

770 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question