Temporary Tables
There is a feature of SQL I have not seen used much and probably with good reason. […]
Theory and design
VIEW Objects
A view is a virtual table, created when it’s invoked by the < view name>. The goal […]
Data Control Language (aka Security)
Like ancient Gaul, SQL is divided into three sub- languages. The DDL (Data Declaration Language) declares the […]
Transactions
By now, pretty much everyone has heard the stories about the first computers. They were huge, cost […]
Consistency and Concurrency in NewSQL Database Systems
Companies today require database systems that are reliable and capable of efficiently handling large volumes of data […]
Rounding Numbers
I would hope by now everybody has figured out when you see a price like $39.99 that […]
Database Sharding: Strategies for Seamless Scaling and Performance Optimization
Companies of all sizes and across industries are struggling to cope with an explosion of data never […]
Uniqueness, Keys, and Identity
If you’ve ever had a traditional logic course, you’ll have run into “The Law of Identity” as […]
Bad Data and Dirty Databases
Many years ago, my wife and I wrote an article for Datamation, a major trade publication at […]
LIKE Constraints
In this article, I will cover a bit about the LIKE operator, including how it works, and […]
Concepts and Issues in Test Data Generation
Data generation is the science and art of providing data for database development work that is as […]
The CHECK() Constraint
One of the many ways a relational table differs from the file structures used by pre-relational storage […]
Database Subsetting and Data Extraction
Let’s start by defining a subset and why you would require a data subset? When dealing with […]
SQL Logic
In this article, I will discuss the history and thinking behind several types of logic that are […]
Department of Redundancy Department
Ever wonder all the reasons that we use databases instead of file systems? While we don’t think […]
Two-Dimensional Interval Packing Challenge
Packing intervals is a classic SQL task that involves packing groups of intersecting intervals to their respective […]
Eager Aggregation in SQL queries
Aggregation is a widely used way to summarize the content of a database. It is usually expressed […]
Using a SQL Tokenizer
Imagine this: you have several directories full of SQL script files, and you need to know where […]
When an update doesn’t update
Tell me if you’ve heard this one before: I changed data from my application, but when I […]
The NTILE Function
The SQL NTILE() is a window function that allows you to break a table into a specified […]
First Normal Form Gets No Respect
Dr. Codd first described the relational model in a paper in Communications of the ACM (CACM 13 […]
T-SQL Fundamentals: Controlling Duplicates
When people start learning a new field, for example T-SQL, it’s tempting to spend very little time […]
The GROUP BY Clause
When you’re learning SQL DML, the most complicated clause is typically the GROUP BY. It’s a fairly […]
Getting Out of Character
Pre-Unicode Younger programmers have grown up with ASCII and Unicode as the only ways of representing character […]