Powershell and SQL parameters. If empty string, pass DBNull

Question

I got this parameter:

$objDbCmd.Parameters.Add(\"@telephone\", [System.Data.SqlDbType]::VarChar, 18) | Out-Null;
$objDbCmd.Parameters[\"@telephone\"].Value =         


        

Answer 1

In PowerShell, you can treat null/empty strings as a boolean.

$x = $null
if ($x) { 'this wont print' }

$x = ""
if ($x) { 'this wont print' }

$x = "blah"
if ($x) { 'this will' }

So.... having said that you can do:

$Parameter.Value = $(if ($x) { $x } else { [DBNull]::Value })

But I'd much rather wrap this up in a function like:

function CatchNull([String]$x) {
   if ($x) { $x } else { [DBNull]::Value }
}