Powershell Error - Null/Empty Argument

Question

I have a small powershell script that is meant to get column ServerName from a remote SQL database called, Hal0Test > from table, ServerList. However, I can not figure out this Powershell Error.

Newest Code:

Write-Output " `n Start of Hal0 `n";

$connectionString = "Server=QAUTILITYDB01;Database=Hal0Test;Integrated Security=True;"
$connection = New-Object System.Data.SqlClient.SqlConnection
$connection.ConnectionString = $connectionString
$connection.Open()
$command = $connection.CreateCommand()

$ServerArray = [System.Collections.ArrayList]@()
$query = "SELECT ServerName FROM ServerList"
$command.CommandText = $query
$ServerNames = $command.ExecuteReader()

$table = new-object “System.Data.DataTable”
$table.Load($ServerNames)

$ServerArray = $table | select -Expand ServerName

$ServerArray | ForEach-Object {
    # $Server returns each server name
    $os    = Get-WmiObject -Class Win32_OperatingSystem -Computer $_
    $disks = Get-WmiObject -Class Win32_LogicalDisk -Computer $_ |
             Where-Object {$_.DriveType -eq 3} |
             ForEach-Object {
                 '{0} {1:D} MB Free/{2:D} MB Used' -f $_.DeviceID,
                     [int]($_.FreeSpace/1MB), [int]($_.Size/1MB)
             }

    New-Object -Type PSCustomObject -Property @{
      'FQDN'            = $_
      'ServerName'      = $os.PSComputerName
      'OperatingSystem' = $os.Caption
      'Disks'           = $disks -join ' | '
    }
    $command.CommandText = "UPDATE ServerList SET FQDN = '$_', OS = '$os.Caption' WHERE ServerName = '$os.PSComputerName';"
    $result = $command.ExecuteNonQuery()  
} | Export-Csv 'C:\Users\king\Desktop\HalO\output.csv' -Delimiter '|' -NoType
Write-Output "`n End of Hal0";

SQL Table:

enter image description here

Ansgar Wiechers · Accepted Answer · 2015-06-19 15:25:27Z

3

You changed my ForEach-Object loop to a foreach loop. If you want to use the latter you need to change the current object variable $_ to your loop variable $Server:

foreach ($Server in $ServerArray) {
  $os    = Get-WmiObject -Class Win32_OperatingSystem -Computer $Server
  $disks = Get-WmiObject -Class Win32_LogicalDisk -Computer $Server | ...

  ...
}

otherwise you need to change the loop back to a ForEach-Object loop:

$ServerArray | ForEach-Object {
  $os    = Get-WmiObject -Class Win32_OperatingSystem -Computer $_
  $disks = Get-WmiObject -Class Win32_LogicalDisk -Computer $_ | ...

  ...
}

Also, there's no pipe between } and Export-Csv:

    $result = $command.ExecuteNonQuery()  
} Export-Csv 'C:\Users\mdaraghmeh\Desktop\HalO\output.csv' -Delimiter '|' -NoType
 ^
here

And even if there were would the foreach loop still be unable to feed its output into the pipeline. If you want to use foreach with a pipeline you must assign the output to a variable:

$output = foreach ($Server in $ServerArray) { ... }
$output | Export-Csv ...

or run it in an expression:

(foreach ($Server in $ServerArray) { ... }) | Export-Csv ...

For direct pipeline processing you need a ForEach-Object loop:

$ServerArray | ForEach-Object { ... } | Export-Csv ...

edited Jun 19, 2015 at 15:25

answered Jun 19, 2015 at 14:20

Ansgar Wiechers

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9 Comments

TheAce Over a year ago

For the direct pipeline I do not understand, I have editted my code to reflect your advice.

TheAce Over a year ago

So add a "|" between } <HERE> Export-Csv and for the direct pipeline what goes into the loop {...}? What I am misssing in my new code?

Ansgar Wiechers Over a year ago

The ellipsis (...) is just a placeholder for the code from the body of your loop. Why do you think you need to change anything there?

TheAce Over a year ago

I do not know what to make the loop do lol? Honestly I am very confused and would love the help. For this is first project like this and I would like to do more to get the hang of Powershell/SQL

Ansgar Wiechers Over a year ago

What's wrong with leaving the code inside the loop as it is? Does something not work as expected? Do you get an error?

|

CB. · Accepted Answer · 2015-06-19 14:14:48Z

2

You need to use a [datatable] to store the result of your select:

$connectionString = "Server=QAUTILITYDB01;Database=Hal0Test;Integrated Security=True;"
$connection = New-Object System.Data.SqlClient.SqlConnection
$connection.ConnectionString = $connectionString
$connection.Open()
$command = $connection.CreateCommand()

$ServerArray = [System.Collections.ArrayList]@()
$query = "SELECT ServerName FROM ServerList"
$command.CommandText = $query
$ServerNames = $command.ExecuteReader()

$table = new-object "System.Data.DataTable"
$table.Load($ServerNames)

Now $table has your servers name list.

answered Jun 19, 2015 at 14:14

CB.

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3 Comments

TheAce Over a year ago

Thank you @CB. but now I am gettig a weird error as well as an InputObject command in the console.

CB. Over a year ago

@TheAce the result of your select is in $table. You don't need any more $servernames.read() ... you follow me? Need to change foreach($Server in $ServerArray) in foreach($Server in $table) and go

TheAce Over a year ago

would you mind editting your answer with the full code for I am not completetly getting what you are saying. Sorry about that

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