@Cryze Zhang - it looks like this was an issue in prior versions as well.  

Did you know you can report this directly to the InterSystems Documentation team?  Click on the blue "Feedback" button on the right side of the screen and it will give you a chance to tell Docs directly what is wrong with the page.  Here is the 2021.1 link you can use for your convenience:
https://docs.intersystems.com/irislatest/csp/documatic/%25CSP.Documatic....

 

Thank you for noticing this and bringing it to our attention!  Please confirm once you have reported the issue and it will get addressed.

@Andrew Barber - welcome to the community!

The links above were from out HealthShare documentation which is protected, however the content is identical in our InterSystems IRIS documentation which anyone can access.  Here are the pages shared by @Stephen Canzano but from our open docs:

https://docs.intersystems.com/irislatest/csp/docbook/DocBook.UI.Page.cls?KEY=RSQL_createview

https://docs.intersystems.com/irislatest/csp/docbook/DocBook.UI.Page.cls?KEY=RSQL_createtable

https://docs.intersystems.com/irislatest/csp/docbook/DocBook.UI.Page.cls?KEY=RSQL_createfunction

https://docs.intersystems.com/irislatest/csp/docbook/DocBook.UI.Page.cls?KEY=RSQL_createquery

Basically, you can do everything in InterSystems IRIS that you can in traditional relational DBs but you get object-oriented access thrown in as well.  So classes and tables are two views on the same persistence.  I suggest the following primers to help you start getting your head wrapped around it:

https://community.intersystems.com/post/classes-tables-and-globals-how-i...

https://docs.intersystems.com/irislatest/csp/docbook/DocBook.UI.Page.cls... (see the table comparing Object vs SQL concepts)

And a deeper dive into how it all works together:

https://docs.intersystems.com/irislatest/csp/docbook/DocBook.UI.Page.cls...

(or from the OO lense: https://docs.intersystems.com/irislatest/csp/docbook/DocBook.UI.Page.cls...

Hope that helps get you started.  Keep asking questions - the Community is a great place to learn!

@Hugh Badian  - I suggest you add the tag 'CCR' to your question.

The %Studio.SourceControl.CCREventHandler.cls is included in the CCR Client Tools so you should be able to open that on any CCR Client system to look at the methods that you can extend to do things on ItemSet download or Refresh.  It has a lot of built-in documentation.

Is there a specific thing that you are looking to accomplish with a CCREventHandler?