[SalesForce] Document and ContentVersion

Content Document: It Represents a document that has been uploaded to a library in Salesforce CRM Content or Salesforce Files. The maximum number of documents that can be published is 30,000,000. This object record you don’t have to create. It gets created when you create ContentVersion which is the child of ContentDocument.

Content Version: Represents a specific version of a document in Salesforce CRM Content or Salesforce Files. In other words, this object stores document information similar like Attachment.

Now have a look on the relationship between these two objects below-

Now ContentDocumentLink: This object will share the files with Users, Records, Groups etc. You can create multiple records to attach the same files under multiple records.

Some useful SOQL queries on Content Version and Content Document-

1.Get Content Document Id by Content Version Id

SELECT ContentDocumentId from ContentVersion where Id = '068......'

2.Get Content Version Id by Content Document Id

SELECT Id from ContentVersion where ContentDocumentId = '069......'

3.Get Download Number of Document by Version

SELECT Count(Id), ContentVersionId FROM ContentVersionHistory where field='contentVersionDownloaded' and ContentVersion.ContentDocumentId  = '069....'   group by ContentVersionId

4.Get Total Download Number for a Document

SELECT Count(Id) FROM ContentVersionHistory where field='contentVersionDownloaded' and ContentVersion.ContentDocumentId = '069....' group by ContentVersion.ContentDocumentId

That's all from my end. I got these from different resources. Thanks.

To solve your purpose trigger needs to be invoked on ContentDocumentLink.

When you are uploading the file from File Tab trigger will fire on "ContentVersion" object, but when you are uploading file from Chatter tab you need to write trigger on "ContentDocumentLink" object.Then only you will be able get the Content Document Id.

It seems like a standard feature of salesforce that the triiger on contentVersion doesn't get called when you are uploading the file from File Tab.