API Environment

The API is packaged as a set of COM Dynamic Link Libraries (DLL) and works as a part of a customer process. EAL.dll is responsible for launching the API environment. When erwin DM is installed, EAL.dll and the rest of the API components are copied to the erwin Data Modeler directory, and the installer registers the API with the System Registry.

To use the API in a development environment, use the API Type Library embedded as a resource in the EAL.dll file. This operation is language specific. Consult your development environment documentation for details.

The API works in two different modes, standalone mode and add-in mode.

The API is activated and controlled by a client application that hosts its own process in the standalone mode.

In the add-in mode, the API is also activated and controlled by a client application, but the client application is implemented as a COM DLL. The erwin DM executable owns a process and all the client application DLLs run inside of that process. COM DLLs must be registered with the System Registry and with the erwin DM Add-In Manager so that it can be available for add-in mode activation.

Behavior of the API components in both modes is the same with a few exceptions that are discussed further in this section.

The API is implemented as a tree of COM interfaces. The application exports the top-level interface, from which the client fetches lower‑level interfaces as needed.