ESI Sources

The look and feel of the end user interface of your application is constructed by the External Schema Interpreter (ESI). ESI takes its information from a number of different data sources or ESI sources:

·	Conceptual repository.

·	Default look and feel.

·	ESI repository.

·	Other GUI applications acting as templates.

Conceptual repository

The definitions of your tables, columns, relationships, etc., are kept in the so-called conceptual repository. "Conceptual" refers to the fact that these are logical specifications instead of tangible look and feel specifications.

Default look and feel

USoft Developer is able to produce a fully functional prototype or default interface from these conceptual definitions alone. For example, on the basis of a column definition, text boxes or other controls are generated in the appropriate windows to display column values and to allow the end user to manipulate these values.

The default look and feel of windows and other interface elements also depends on settings taken from a file named USDINIT.ESI. For example, this default look and feel determines that text boxes in info windows appear in a vertical instead of a horizontal arrangement, that they are left-aligned independently of prompt length, and that related windows display five records at a time.

External repository

The USoft Windows Designer allows you to change the default look and feel of your application by making additional specifications about what the interface should look like and how it should behave. These additional specifications are kept separately in so-called ESI tables, also referred to as the external repository.

For example, you can add a button to an info window and enable the USoft end user to perform a particular action by clicking it, such as sending an email or navigating to another interface. Or you can decide to have dates shown in a specific format in certain windows only. These external definitions change the look and feel and even the functionality of the application, but they do not depend on conceptual definitions.

GUI applications and templates

Finally, using the New Application option, you can create more than one GUI application for the same set of "conceptual" specifications.

You can even specify that your GUI application should re-use all or some of the GUI classes (windows, dialogs, controls) of another GUI application. You do this by specifying that one GUI application is the template for another. If you use these facilities, the source for the default look and feel from which you "paint" is not just the USDINIT.ESI files but also one or more .ESI template files.

In summary, the end user interface of your application is built from the following sources:

·	Definitions in the conceptual repository.

·	Default look and feel specifications stored in files (including template files).

·	Definitions in the ESI tables.