Compare database table with XML contents. Kept for code that extracts parameters from a query string, adds them to a SqlCommand and copies values from variables with the same name.

sqlxml.ps1

$cn = new-object Data.SqlClient.SqlConnection 'Server=.;Database=CIA;Trusted_Connection=true'
$cn.open()

$q = @'
select count(*) from journaalposten.unv_conversierekeningschema
where grootboeksysteem='QIS' and maatschappij=@m and gb_rekening=@gbr and kostenplaats=@kp and kostendrager=@kd
'@
$cm = new-object Data.SqlClient.SqlCommand -a $q, $cn

$p = $cm.parameters
[regex]::matches($q, '@\w+') | % { $p.addwithvalue($_.value, '') } | out-null

[xml]$x=gc *.xml
$cs = @()
foreach ($e in $x.ledgerEntryList.ledgerEntry) {
    $m = $e.businessUnitRef.externalIdentifier
	$yd = if ($e.yearDamage.nil -eq 'true') { '' } else { $e.yearDamage }
	foreach ($l in $e.ledgerEntryLineList.LedgerEntryLine) {
		$gbr = $l.amtTypeCode
		$kd = if ($l.productVersionCoverageExternalCode.nil -eq 'true') { '' } else { $l.productVersionCoverageExternalCode }
		$kp = if (-not $yd -and $kd) { '0' } else { $yd }
		$p | % { $_.value = (get-variable $_.parametername.substring(1)).value } | out-null
		if (-not $cm.executescalar()) {
			$cs += "$m.$gbr.$kp.$kd" -replace '\.\.$',''
		}
	}
}
$cn.close()
$cs | group | select name | sort name