How to update parentID on Attachments in Salesforce

Question

I need to move Attachments from one SF to another SF, but the final parent object is not in the destination org. So I've created temporary records and plan to update the ParentId of the attachments later.

But when I was ready to update the ParentId of the Attachments, it didn't show a map to the "parentID". I read somewhere that when we insert Attachments its parentID becomes read-only after insertion. I loaded around 6GB of data to my temporary records. How can I modify the ParentIds of all those Attachments?

Answer 1

You can clone the entire attachment and then delete the old one.

this code works for me :

List<Attachment> attachmentsToInsert = new List<Attachment>();

List<Attachment> attachmentsToDelete = new List<Attachment>();

Attachment tempAtt;


for(Attachment attachment: [
        SELECT SystemModstamp, ParentId, OwnerId, Name, 
            LastModifiedDate, LastModifiedById, IsPrivate, IsDeleted, 
            Id, Description, CreatedDate, CreatedById, 
            ContentType, BodyLength, Body 
        FROM Attachment 
        WHERE parentId=:'parentid']) {

    tempAtt=attachment.clone(false,false);
    tempAtt.parentId = quoteSelWrap1.quot.Id;

    attachmentstoInsert.add(tempAtt);
    attachmentsToDelete.add(attachment);

}

insert attachmentsToInsert;
delete attachmentsToDelete;

Answer 2

ParentId is not updatable on Attachment, as you've discovered. This means you will not be able to modify the existing attachments to reparent them to a new parent.

You will probably need to use an external ID on the parent records when you load the attachments in the first place.

This involved setting either a text, number, or email field to both ExternalId and Unique.

Let's say you do this with Account and you add the External Id field called Import_Key__c. Once you've added that field you will need to populate it with a unique value. This can be anything, even a duplicate of the record Id.

Then your mapping will look something like this:

SourceField          Salesforce Field
---------------------------------------------------------------------
ParentId             Parent.Import_Key__c

You need to then use the Upsert operation. When upserting the attachment, salesforce will use the external Id field value to map back to the proper parent record Id and populate ParentId with the correct value.

Yes, you will need to reload all 6GB of those attachments, but I'm afraid it is the only way.