How to modify internalname in Sharepoint 2010 list field - powershell

Question

I need to change the internalname for a sharepoint 2010 list item field. For some reason, our migration software renamed it during 2007->2010 migration and this field is referenced by other processes so we need the internalname back to the original. This field exists in over 200 lists in the migrated site so we need a means to do this programatically - powershell preferred.

Answer 1

$newInternalName = "yourInternalFieldName"
$displayName = "oldDisplayName"
$SPWebApp = Get-SPWebApplication "http://yourwebapp"
foreach (SPList $currList in $SPWebApp.Lists)
{
foreach (SPField $fld in $currList.Fields) #you could potentially use a different command here to get the field more efficiently
{
if ($fld.Name == $displayName)
{
#The boolean in the parameter list is for required/non-required field $currList.Fields.Add($newInternalName,Microsoft.SharePoint.SPFieldType.Text,$False)
foreach (SPListItem $item in $currList.Items)
{
$item[$newInternalName] = $item[$displayName]
$item[$newInternalName].Title = $displayName #I'm assuming you want to keep the display name the same
$item.Update()
}
Break #since you've already fixed the column for this list no need to keep going through the fields
# optional delete unwanted column
# $currList.Fields.Delete($displayName)
# $currList.Update()
}
}
}
As far as I know, you cannot change the internal name of a field once it has been created. Here I create a new field with the correct internal name and copy over the values. I don't have access to a server with Powershell today so I wasn't able to test this, but this should be very close to what you need. You may need to tweak it a bit based on what type of field you're dealing with, if you want to use a different Add function, and/or you want to delete the old field.
The enumeration to select the type of the field in the Add function is defined here:
http://msdn.microsoft.com/en-us/library/office/microsoft.sharepoint.spfieldtype(v=office.14).aspx
There are a couple of overloads for the Add function so if the one I used doesn't work for you, you might wanna use one of these others
http://msdn.microsoft.com/en-us/library/office/aa540133(v=office.14).aspx