Arun Garg 3/02/2022 salesforce lightning developer Comment

Delete files, Change related record of files / Attachments / ContentDocument/ ContentDocumenLink from object by Apex.

Here we will consider the examples of files on Account object. Actually we can not directly change the related record id on files. To change related id we have to follow below steps:

1. First , files are stored in contentDocument object and linked with ContentDocumentLink object.

2. So if you want to update related record id then you must have to updatte ContentDocumentLink object.

3. But Related Object Id is stored in LinkedentityId field of ContentDocumentLink object and this field can not be overwritten. so we can not directly change related record Id.

4. Then to change related record id , we first need to delete record of ContentDocumentLink object then insert new record with same data with your new related record Id.

Lets see steps below:

To fetch files , use below query

List<ContentDocumentLink> listContentLink = [Select Id,Linkedentity.name,LinkedentityId,ContentDocumentId from ContentDocumentLink Where LinkedentityId='0017F00001eFkvN']; //LinkedentityId - is Account Id

List<ContentDocumentLink> listCloneData = new List<ContentDocumentLink>();

List<ContentDocumentLink> listDeleteData = new List<ContentDocumentLink>();

for(ContentDocumentLink objConDoc : listContentLink){

ContentDocumentLink objCloneContentDoc = objConDoc.clone(); // Take clone of existing data

objCloneContentDoc.LinkedentityId = '0017F00000yz5xpQAA'; // Assign new account record Id

listCloneData.add(objCloneContentDoc); // add new data in clone list

listDeleteData.add(objConDoc);

}

// First insert data

if(!listCloneData.isEmpty()){

insert listCloneData;

}