From: uunet!mwhhlaw!bob (Robert L. Hartley Jr.)
Subject: Re: DBKit Help (puhleeze)
Reply-To: bob@mwhhlaw.com
Organization: Martin Wade Hartley & Hollingsworth
Date: Fri, 21 Aug 1992 18:32:05 GMT

In article <1992Aug20.224819.1@capd.jhuapl.edu> waltrip@capd.jhuapl.edu  
writes:
> If you can find the time
I don't know if it's a question of time.  We signed contracts not  
circulate Beta stuff.

Maybe this will help.  To use use DBKit you must have an "Adaptor" to  
your database.  3.0 will have Sybase and Oracle adaptors with it.  Then  
within Sybase or Oracle you have to build your tables.  Then you run a  
program called DBModeler, in which you spell out to DBKit what parts of  
your database you want your application to see, and how you want them  
to be seen.  Essentially a table is called an entity, and a column or  
field is called a property.  You select entities and properties.  You  
establish relationships between any two (note this limit) properties in  
the same entity or different entities.  Your model can include as many  
relationships as you want.  After you have made your model, you can use  
Interface Builder, in which DBKit must be loaded as a palette.  On that  
palette, you find three icons.  One represents a DBModel, which you can  
drag into your application, and then you get access to all the  
entities, properties, and relationships you included in your model  (I  
think you can include more than one DBModel if you want.)  The other  
two icons on the palette represent interface objects.  One is an image  
field, which you can drag into a window and to which you can then  
connect to a property in the DBModel.  You would use an image to  
display data from binary fields.  The other is a Table View (much like  
a browser), which has rows and columns and is scrollable, which you can  
drag onto a window and to which you can connect properties from your  
model.  You can also connect properties from your model to other  
palette object like views, text fields, etc.

About the time 3.0 comes out look for some third party objects and  
palettes to enhance the list of interface objects to which properties  
from the model can be connected.

From my limited experience so far, you can only do the simplest of  
database operations with interface builder.  To do anything  
sophisticated, you must write the code.  DBKit includes dozens of  
objects and methods by which you can do this.  But it is complex.  As I  
understand it, DBKit keeps the stuff it gets from the database in  
stream objects.  It keeps all the display stuff in other objects, and  
another set of objects keeps the streams and display objects in sync.

While DBKIt appears very rich in functionality, it does have limits.   
For example the relationships is recognizes are not in any way complex.   
Since there are mechanisms to pass SQL commands through to the  
database, I assume that with enough effort, one could programatically  
accomplish about anything, but the solution would not necessarily be  
elegant.

Without sending you the Beta documentation (which we are not allowed to  
do), I don't know what else to say.



-- 
Bob Hartley
MARTIN, WADE, HARTLEY & HOLLINGSWORTH
P. O. Box 88676
3590 N. Meridian St.
Newsgroups: comp.sys.next.programmer