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Data Management (RSS)

Sunday, September 06, 2009 9:13 PM

But it worked fine on my machine!

How many times have you thought that? Or even worse, actually heard yourself saying it? Come on, now, be honest! When you hear that, in the context of an application, or some screen or function within an application, what does it really mean? Basically
posted by andykr | 5 Comments
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Attachment(s): GenData.zip
Tuesday, August 18, 2009 10:34 AM

So, what's so bad about Public Variables?

Every once in a while the question about whether Public Variables are something that should be used in VFP. Now, there are lots of opinions on this matter and there are several arguments that come up time and time again in defense of using Public Variables.
posted by andykr | 2 Comments
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Attachment(s): variableclass.zip
Sunday, May 10, 2009 12:59 PM

Modeling Lookup Tables

One topic that caught my eye on the Foxite forum recently was a discussion of how to implement Lookup Tables. Like many such questions it provoked strong opinions and definitive statements of the "Thou shalt ...." type (i.e. the type of "dogmatic logic"
posted by andykr | 7 Comments
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Sunday, May 03, 2009 3:18 PM

Working with Vertical Tables

What is a "Vertical Table"? The short answer is that a vertical table is one which does not store data elements in separate columns. Instead data is stored in rows, with each row containing a description of what is being stored (the “attribute”) and the
posted by andykr | 3 Comments
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Saturday, April 25, 2009 2:50 PM

Modeling Hierarchies (Part 2)

In the last article I gave the theoretical background to using mapping to model complex hierarchies. In this article I will work through an example that is intended to illustrate how the use of the mapping approach can solve some of the key issues associated
posted by andykr | 5 Comments
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Attachment(s): ripdemo.zip
Saturday, April 18, 2009 1:21 PM

Modeling Hierarchies (Part 1)

As a computer users, we deal with hierarchies every day and working with relational data involves hierarchical relationships of varying degrees of complexity from the simple parent-child-grandchild (e.g. Customer -> Order -> Item) to very complex
posted by andykr | 2 Comments
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Saturday, March 21, 2009 1:10 PM

Getting to Grips with SQL (Complex Queries)

In the introduction to his book “SQL For Smarties” (Morgan Kaufman, ISBN 1-55860-576-2) Joe Celko makes the point that often simply changing the way you approach a difficult problem can often help in resolving it. He goes on to offer a number of tips
posted by andykr | 2 Comments
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Saturday, March 14, 2009 10:34 AM

Getting to Grips with SQL (Sub-Queries)

A sub query, as the name implies, is simply a query that is contained within another query. The purpose of a sub query is to return one or more values to the outer query and there are three basic types of sub query: Sub queries that generate a list
posted by andykr | 4 Comments
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Sunday, March 08, 2009 7:05 PM

Getting to grips with SQL (The basics)

Looking back through the series of articles that I have published on my blog over the past couple of years I see that I have not specifically addressed the use of Structured Query Language (SQL). So it's time to remedy that omission. Before we can begin
posted by andykr | 4 Comments
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Sunday, December 14, 2008 3:20 PM

Designing a Database - Part 5

So far I been concentrating on the logical design for a database – the system scope, types of tables, relational patterns and rule management. The next stage is to consider the physical design which is, after all, what an application will have to deal
posted by andykr | 1 Comments
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Sunday, December 07, 2008 12:25 PM

Designing a Database - Part 4

In the previous three articles I have talked about the various components that comprise a database design. The logical model, and how it relates to the business process, the various structural patterns for tables and the relational patterns that we use
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Sunday, November 23, 2008 1:01 PM

Designing A Database -Part 3

---------------------------------------------------------------------------------- 12/03: Sorry for any inconvenience - somehow I forgot to 'publish' the pictures for this article and since I only reviewed it while logged in to the site as the owner,
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Sunday, November 16, 2008 12:50 PM

Designing A Database – Part 2

In the first article in this series I was careful to refer to data (and to differentiate it from ‘information’) only in the most generic sense. It is now important to consider exactly what we mean by data because before we can actually start defining
posted by andykr | 2 Comments
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Sunday, November 09, 2008 11:27 AM

Designing A Database - Part 1

When confronted with the task of designing a database most of us tend to start thinking in terms of tables and columns. This is, generally, a mistake! The reason is that before we can really start to design tables we need to understand the function of
posted by andykr | 1 Comments
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Saturday, October 11, 2008 12:12 PM

Key Design Considerations for a Client Server Application

Whilst it is impossible to be prescriptive about how to build and implement a Client/Server application in the absence of detailed requirements and specifications, there are issues that are common to all applications and which need to be handled differently
posted by andykr | 2 Comments
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