Understanding Salesforce Files - ContentDocument, ContentVersion & ContentDocumentLink

 

 

Content Document object
               It represents a document that has been uploaded to a library in Salesforce CRM Content or Salesforce Files. It’s the parent object of both ContentVersion and ContentDocumentLink; when a ContentDocument record is deleted, all its child records are deleted as well. ContentDocument is automatically created when a ContentVersion without an associated ContentDocumentId is added to a Salesforce org. This can occur when a new file is uploaded via the Salesforce UI or when a ContentVersion without ContentDocumentId is created programatically.

Supported Calls

delete(), describeLayout(), describeSObjects(), query(), retrieve(), search(), undelete(), update()

Check out Salesforce's Developer Guide for a full breakdown of the ContentDocument object, including a complete list of fields, a rundown of special access rules, usage tips, and more.

Content Version object
               It represents a specific version of a document that has been uploaded to a library in Salesforce CRM Content or Salesforce Files. This is where the actual content of a file is stored. ContentVersion is created when you upload a file or document to Salesforce or add a new version of an existing one. When you create a ContentVersion that is not associated with an existing ContentDocument, Salesforce automatically creates a parent ContentDocument object and a child ContentDocumentLink that looks up to it. It may seem counterintuitive that creating ContentVersion is what sparks the creation of its parent ContentDocument and not the other way around.

Supported Calls

create(), describeLayout(), describeSObjects(), query(), retrieve(), search(), update(), upsert()

ContentVersion Key fields

Again, comprehensive documentation for the ContentVersion object can be found in Salesforce's Developer Guide.

Content Document Link object
               It is a junction object that represents the link between a file and the entities it's shared with: other users, groups, records, and libraries. ContentDocumentLink is created when its parent ContentDocument is created. If a file is added from the Files tab, a single ContentDocumentLink record is created that looks up to its parent document via the  ContentDocumentId field and to the user that uploaded it via the LinkedEntityId field. However, if a file is added in the context of another object, such as a related list on a record page, two ContentDocumentLink records will be created: one that looks up to the user that uploaded it, and one that looks up to the object it is associated with.

Supported Calls

create(), delete(), describeSObjects(), query(), retrieve(), update(), upsert()

ContentDocumentLink Key fields

• ContentDocumentId – This is a lookup field used to associate the ContentDocumentLink with its parent ContentDocument object.
• LinkedEntityId – This is a reference field that is used to associate the ContentDocumentLink with entities it is linked to, such as users and records.
• ShareType – This is a picklist field that determines the permission granted to the user of the shared file in a library. There are three available options:
  V – Viewer permission: The user can explicitly view but not edit the shared file.
  C – Collaborator permission: The user can explicitly view and edit the shared file.
  I – Inferred permission: The user’s permission is determined by the related record. For shares with a library, this is defined by the permissions the user has in that library.
• Visibility – This is a picklist field that determines whether the file is available to all users, internal users, or shared users.

As always, Salesforce's Developer Guide is your source for full documentation of the ContentDocumentLink object.