Are Work Item IDs unique in TFS, even when using multiple projects?

Question

This feels more like an 'English' question than a 'Stack Overflow' question, but I'm about to commit to a data structure that will be very hard to change later, so I wanted to be absolutely sure about this.

https://learn.microsoft.com/en-us/azure/devops/boards/queries/titles-ids-descriptions?view=azure-devops

This documentation states that the ID field of a Work Item is unique across all projects and within a project collection. If I am reading that correctly, this means that once a Work Item of any type - User Story, Ticket, Data Fix, Bug, Code, whatever - has been created inside one project with one ID, then no other project on the same TFS server will ever use the same ID number for a work item of any type, in any project? Even once a Work Item has been closed - possibly deleted - the same ID number will never be reused?

Answer 1

From this official document,we can confirm that work item ID is unique identifier which is assigned by system.

We can also certify this by testing. We create a task item in project 1, the assigned id is #210, then we create another same item in project ed, and the assigned id is #211. It can be seen that the id assigned by the system is incremented in order.

Then we delete the item with id #211, and then create a new item in project1. The newly created item has an id of #212. It can be seen from this that the id of the deleted item is not reused.

In summary,it can be sure that Work Item IDs are unique across all projects. You don't worry that work items with the same id appear in different projects.

Answer 2

Yes. You read it right. Work item IDs are unique for a collection though you delete/destroy one.