This allows you to make interrepository transfers with much less programming, thereby saving a lot of time. However, the source system in many cases is a legacy system involving many flat files. In such cases, use user extensions. You can either start from ground zero by creating all the necessary extensions manually or load them from another Designer repository by using an extract file. The latter option is especially powerful, since it facilitates sharing of all commonly required user extensions between sites.
Designer imposes some restrictions on user extensions.
For instance, an extension element-type name must start with an E and the second character must be a number from 0 to 9. For most user-extension types, Name and Comment are additional predefined attributes. Listing 3, the API code sample from our library, shows how specific instances of flat files are created with the ADD operation. The structure of these tables varies from site to site, depending on the information about the flat files that needs to be captured and entered into the repository. I've only touched the tip of the iceberg in outlining the ability of the Designer repository to serve as your core repository.