This is not new news, but I couldn’t find information on it at first. Most BCS examples and implementations tend to be small so you don’t see this often:
[box type=”info”] Application definition import failed. The following error occurred: Cannot create more than ’20’ IIdentifier objects per IEntity object. Error was encountered at or just before Line: ‘199’ and Position: ’14’. [/box]
In a nutshell, you cannot load more than 20 identifiers per the BCS specification (even if the BCS tools allow you to add more).
SharePoint 2010 BCS Identifier Element
SharePoint 2007 BDC Identifier Element
Hope this helps someone.