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Tech-ed Topic Summary; something missing?
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From
17/03/1999 13:38:15
 
General information
Forum:
Visual FoxPro
Category:
Conferences & events
Miscellaneous
Thread ID:
00193227
Message ID:
00198722
Views:
43
Hi Marc ---

You don't have to be a computer scientist to run through an architectural phase on *any* size project. You probably are already doing it at at smaller scales through hand sketches, notes with arrows pointing about, etc.

IMHO if you follow a good methodology (preferably OOAD) to model (paper or prototype) an application before coding, then some of the tiers should start to emerge from the design.

As Jim succinctly pointed out to me, n-tier is a design philosophy. Within a single language platform like VFP it's easy to experiment. Lets look at the three basic tiers:

Presentation tier (UI, screens, reports)
Business Services tier (validation, business computations)
Data Services tier (read/write data, prepare queries, et al)
Data store (the physical DBF)

Sometimes the 3rd and 4th tiers are combined.

Look at the way you already build VFP applications. Do you have an Application object? Odds are you do so there is a rudimentary Business services tier. Do you have forms and reports? Then you have a presentation tier.

Do you use remote views? Then the DBC connection and the ODBC function as the transport mechanism of a Data Services tier.

I guess what I am saying is that, by definition, most VFP applications are already inherently n-tier .
------------------------------------------------
John Koziol, ex-MVP, ex-MS, ex-FoxTeam. Just call me "X"
"When the going gets weird, the weird turn pro" - Hunter Thompson (Gonzo) RIP 2/19/05
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