Author: Robert Hamel

Book Review of Guy Harrison’s Oracle Performance Survival Guide

This is the first time I have read one of Guy’s books and I was very impressed at the breadth of topics that are addressed and especially the approach that is followed starting from the application design rather than trying to find the elusive fast=true setting that resolves every problem.

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Simple MySQL Auditing

Simple auditing can save you tons of time while troubleshooting. I came up with some simple stored procedure that will compare two data sets and keep track of the changes historically. It’s loosely based on slowly-changing dimension type 2 in the data warehouse world. This method tracks only changes, so you should be able to keep historical rows forever, unless you are constantly dropping and creating whatever you are tracking.

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Date Dimension vs. Function-Based Indexes: Is the Date Dimension Still Relevant?

The purpose of this post is to verify if a date dimension is better in regards to performance and functionality than a series of function-based indexes on a date column in the fact table.

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Oracle 11g: New Pivot Table Feature

I was very pleased when I heard about Oracle adding pivot functionality in select statements. Finally — we wouldn’t have to copy the data to a spreadsheet or code a ton of sum(case when col1 = ‘X’ then amount else 0 end) total_X for each column we would want to display. I am basically looking for three things in a pivot-style query: the ability to specify which column will be pivoted as one or more columns in the resulting query, row subtotals, and column subtotals. The first item is the only one that really matters. I can work around the other two, so let’s get started.

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Implementing Many-to-many Relationships in Data Warehousing

This article will discuss how to make many-to-many relationships in data warehousing easily queried by novice SQL users using point-and-click query tools.

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