SharePoint 2013 - Library - Update an item of type Managed Metadata

Question

I have a document Library.

It contains many columns out of which I want to update the value for managed metadata column.

Suppose, the Value which I want to update is "My Value" and this value "My Value", exists in term store and also in Taxonomy Hidden List.

Below is my code to update the value:

#CAML Query to get Item From Library and Update
        $spQuery = New-Object Microsoft.SharePoint.SPQuery
        $spQuery.ViewFields  ="<FieldRef Name='My_x0020_Prod' />";
        $spQuery.ViewAttributes = "Scope='Recursive'";
        $spQuery.Query = "<Where>                                    
                                  <Eq>
                                    <FieldRef Name='Prod_x0020_ID' />
                                    <Value Type='Text'>" + $prodID  + "</Value>
                                 </Eq>                                         
                           </Where>"
        $col=$list.GetItems($spQuery) 
        foreach ($item in $col)  
        {  
           if($item.Count -gt 0)
            {

                $item["My_x0020_Prod"] = "My Value"
                $item.Update()

            } 
        } 

This code doesnt update the MMD item in the library and throws an error:

The given guid does not exist in the term store

Now, when I go back to the library and manually update the field for the MMD column, it works fine.

Programatically, this is not working and I think I am missing something.

Should I first get GUID from term store and then update the value in MMD?

Answer 1

Yes you cannot update MMD field whose value is not present in termstore

You need to first get the term value which you will be updating

[System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Taxonomy")
$site = Get-SPSite "http://site"
$session = New-Object Microsoft.SharePoint.Taxonomy.TaxonomySession($site)
$termStore = $session.TermStores["TermStore Name"]
$group = $termStore.Groups["Terms"]
$termSet = $group.TermSets["termset"]
$terms = $termSet.GetTerms(number of terms to be retrieved)
$term = $terms | ?{$_.Name -eq "your value"}

And then use $term to update in your code

 $termfield= [Microsoft.SharePoint.Taxonomy.TaxonomyField]$List.Fields["My_x0020_Prod"]

foreach ($item in $col)  
    {  
       if($item.Count -gt 0)
        {

            $termfield.SetFieldValue($item, $term)
            $item.SystemUpdate()

        } 
    }

Answer 2

#Create a Taxonomy Session
 $TaxonomySession = Get-SPTaxonomySession -Site $web.Site
 $TermStore = $TaxonomySession.TermStores[$termStoreName]
 $TermGroup = $TermStore.Groups[$termGroupName]
 $TermSet = $TermGroup.TermSets[$termSetName]

 #Below line of code will get the name, GUID and other properties from TermStore
 $Term = $Termset.Terms[$MMDValueToUpdate]

#This is the Library Item OOTB ID of the item which you want to update
 $item = $list.GetItembyID($ItemID)
 if($item.Count -gt 0)
 {
 $MMSField = [Microsoft.SharePoint.Taxonomy.TaxonomyField]$item.Fields[$FieldName]
 #If value exists in TermStore
 if($Term)
 {
 $MMSField.setFieldValue($item,$Term)
 $Item.SystemUpdate()
 Write-Host "Updated value as: " $Term.Name -backgroundcolo Green
 }
 else
{
Write-Host "Could not find termstore properties for : " $MMDValueToUpdate  -backgroundcolo Red
}