PowerShell to Udpate Active Directory Schema

Update-Schema.ps1

# This should only be used in a development environment and is for demonstration purposes only
# Use at your own risk
# This adds an attribute to the user class
# Written by Andy Schneider, http://get-powershell.com

Function New-OID {
    $Prefix="1.2.840.113556.1.8000.2554" 
    $GUID=[System.Guid]::NewGuid().ToString() 
    $Parts=@() 
    $Parts+=[UInt64]::Parse($guid.SubString(0,4),"AllowHexSpecifier") 
    $Parts+=[UInt64]::Parse($guid.SubString(4,4),"AllowHexSpecifier") 
    $Parts+=[UInt64]::Parse($guid.SubString(9,4),"AllowHexSpecifier") 
    $Parts+=[UInt64]::Parse($guid.SubString(14,4),"AllowHexSpecifier") 
    $Parts+=[UInt64]::Parse($guid.SubString(19,4),"AllowHexSpecifier") 
    $Parts+=[UInt64]::Parse($guid.SubString(24,6),"AllowHexSpecifier") 
    $Parts+=[UInt64]::Parse($guid.SubString(30,6),"AllowHexSpecifier") 
    $oid=[String]::Format("{0}.{1}.{2}.{3}.{4}.{5}.{6}.{7}",$prefix,$Parts[0],
                                    $Parts[1],$Parts[2],$Parts[3],$Parts[4],$Parts[5],$Parts[6]) 
    $oid 
}

Function Update-Schema {
[CmdletBinding(SupportsShouldProcess,ConfirmImpact='High')]
param(

[Parameter(Mandatory,ValueFromPipelinebyPropertyName)]
$Name,

[Parameter(Mandatory,ValueFromPipelinebyPropertyName)]
[Alias('DisplayName')]
$LDAPDisplayName,

[Parameter(Mandatory,ValueFromPipelinebyPropertyName)]
[Alias('Description')]
$AdminDescription,

[Parameter(Mandatory,ValueFromPipelinebyPropertyName)]
[Alias('SingleValued')]
$IsSingleValued,

[Parameter(ValueFromPipelinebyPropertyName)]
[Alias('OID')]
$AttributeID = (New-OID)
)

BEGIN {}

PROCESS {
  
  $schemaPath = (Get-ADRootDSE).schemaNamingContext       
  $type = 'attributeSchema'
  switch ($isSingleValued)
  {
   'True'  {$IsSingleValued = $true}
   'False' {$IsSingleValued = $false}
   default {$IsSingleValued = $true}
  }

  $attributes = @{
      lDAPDisplayName = $Name;
      attributeId = $AttributeID;
      oMSyntax = 20;
      attributeSyntax = "2.5.5.4";
      isSingleValued = $IsSingleValued;
      adminDescription = $AdminDescription;
      searchflags = 1
      }
    
    $ConfirmationMessage = "$schemaPath. This cannot be undone"
    $Caption = 'Updating Active Directory Schema'
    
    if ($PSCmdlet.ShouldProcess($ConfirmationMessage,$Caption))
    {
      New-ADObject -Name $Name -Type $type -Path $schemapath -OtherAttributes $attributes 
      $userSchema = get-adobject -SearchBase $schemapath -Filter 'name -eq "user"'
      $userSchema | Set-ADObject -Add @{mayContain = $Name}
    }
}

END {}
    
}