title: No value given for one or more required parameters. error during Search
body: <p>I am trying to search the data in a simple access database. The code is this</p>
  
  <pre><code>Call connect()
  con.Open()
  cmd = New OleDbCommand("Select * from PO_Record_Table where Customer=asd", con)
  dr = cmd.ExecuteReader
  While dr.Read
      MsgBox(dr(1))
  End While
  
  con.Close()
  </code></pre>
  
  <p>If I press search button, the error: No value given for one or more required parameters
  comes on this line</p>
  
  <pre><code>dr = cmd.ExecuteReader
  </code></pre>
  
  <p>The record "asd" is in the database customer field as a text type.
  Why does this error come and how to finish this search without error?</p>