[TML] Back to the 21st century SQL question.

[Christopher Hilton]

garry.e.ward at worldnet.att.net wrote:

[snip]

> Transactional processing, however, I consider something that should NEVER had gone into the database. 
> 
> Data integrity rules (such as value checking as well as type checking), can often be better served at the client rather than the server unless the data integrity involves referential integrity (can't add a row in table B if field X doesn't match field Y in table A).
> 

Let me start with the blanket statement that I mean no offense to anyone 
when I disagree. I think that the reason that I love Traveller so much 
is because it provokes arguments nearly as strong as those I see in the 
software engineering community.

I disagree on Transactional processing. Having it in the database 
reduces overall code like the try: ... except: blocks in Python or the 
similar construction in Java. I know that it extracts a performance 
penalty but I feel that modern hardware has reduced this cost to the 
point where the tradeoff: slower transactional database vs. faster 
transactionless database is more than paid for by the simplicity of code 
that uses tranactions to insure integrity.

On Data Integrity rules. There is a certain joy that I get from knowing 
absolutely that there is no way to insert a system in hex 9999 when the 
data definition dictates that a sector consists of the area that spans 
from hex 0101 to hex 2440. Yes, this can be insured from the client but 
my experience has me implementing it in both places. My reasons for that 
are simple. Detecting errors on the client side is detecting errors 
early and that can only make your user interface better. Detecting 
errors on the server side guarantees data integrity against access that 
bypasses the client and the UI.

Just from my experience, all the attributes I'm mentioning: referential 
integrity, data consistency, transactional processing; don't seem to be 
all that important at the start of the project. In all of the 
applications that I have built in my life I have never run into a 
project that justified the use of an SQL database and wouldn't have 
benefitted greatly from at least two of these during the application 
life cycle.

-- Chris


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Christopher Sean Hilton                    <chris | at | vindaloo.com>
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