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[About The Guide]
An Overview of Database Design
Databases are the heart of the Expert Help Hypertext System. Almost all
of the information you see in the display window (from pull-down menus
to Related Topics) is stored in the database file. The Database Composer
also puts additional information into the database to speed up the access
to the data.
Pull-Down Menus
Pull-down menus (defined by the author of the database) provide the
basic structure of all Expert Help Databases. Expert Help databases
contain a number of separate, but still related, sections of data.
Each of these sections is accessed through an item in a pull-down
menu. This makes it easy to pinpoint the data you want, or just
browse through the data when you're not sure what you're looking for.
The advantage of menus is that they provide a fairly "flat" database
where short entries (which you can think of as a table of contents)
expand to longer descriptions.
It is possible to build tree structures, where entries in a list are
Expanded into other lists of short entries (sort of like having a book
within a book). Expert Help's Global Search capabilities make finding
this "tree structured" information painless.
Entries
All the data in a Hypertext Database is organized as one of two
structures: short entries and long entries. Short entries are
one-line descriptions that serve as pointers to more complete
descriptions. Those complete descriptions are called long entries.
When you select Expand, you are asking to view the long entry
pointed to by a short entry. A short entry can and usually does
expand (point) to a long entry. Alternatively, a short entry can
expand to a list of short entries, creating a "deeper" database.
Data Text Files
Each item in a pull-down menu points to a separate section of the
database. And each of those sections is created as a separate data
text file. In other words, you will have at least one text file for
each menu item. (You can also use the !file command to build deeper,
more complicated structures - in which case, you will create more
than one source file per menu item.)
As mentioned above, data text files are comprised of short and long
entries. A single text file can contain either a list of short
entries, with their long entries directly underneath, or a single
long entry.
The Composer - (A Compiling and Linking Overview)
At this point you may be wondering how all of these data text files are
transformed into a single Hypertext Database. That's the function of
the Database Composer's Compiler and Menu Linker. The Composer compiles
and links your data text files into a finished Database, complete
with your data, information about menus and menu names, and special
information (included by the Database Composer) to speed access to
your data.
From Data Text Files to Finished Database
After creating the data text files, you need to compile them. The
Database Composer builds intermediate files, which the Menu Linker
uses to build the finished database. These intermediate (or object)
files have the extension .EHO.
The last step in creating a database is linking the compiled
(intermediate) files together using the Database Composer's menu
linker. Linking produces a single file compatible with the Search
Engine. Linking is also the point at which the menu structure of
the database is defined. The menu structure is defined by a text
file called the menu link control file, which the Database
Composer uses as a template for the finished database. The Database
Composer combines the menu information from this file with the data
from the (intermediate) object files to create a finished Hypertext
Database.
Here is a summary of the steps for creating a Hypertext Database:
1. Create text files with your data.
2. Compile each data text file with the Database Composer.
3. Create the menu link control file, which
defines the menu structure of your database.
4. Link the files with Database Composer's Menu Linker.
5. Access the new database with the Expert Help Engine
and review the layout of your information.
Press the Gray + key to proceed to the next topic (long entry).
See Also:
Creating Data Text Files
Data Text Files
Short and Long Entries
Creating Entries
Character Attributes
Adding Comments to Data Files.
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