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SQL Antipatterns: Avoiding the Pitfalls of Database Programming

Solution: Divide and Conquer

Discover how to manage complex SQL queries by dividing them into simpler, manageable components. Learn to avoid unintended Cartesian products and enhance query performance and maintenance, using practical examples and solutions like UNION and code generation.

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A famous quote by William of OckhamEnita non sunt multiplicanda praeter necessitatem (Latin, “Entities are not to be multiplied beyond necessity.”). also known as the law of parsimony, goes as follows:

The Law of Parsimony

This law essentially states that: “When you have two competing theories that make exactly the same predictions, the simpler one is the better.”

What this means in SQL is that when we have a choice between two queries that produce the same result set, we should choose the simpler one. We should keep this in mind when straightening out instances of this antipattern.

One step at a time

When we can’t find a logical JOIN condition between the tables involved in an unintended Cartesian product, it could be because there simply is no such condition. To avoid the Cartesian product, we have to split up a Spaghetti Query into several simpler ...