science

Principle of orthogonal design

Principle of orthogonal design is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Principle of orthogonal design rather than just read about it. In short: The principle of orthogonal design (abbreviated POOD) was developed by database researchers David McGoveran and Christopher J. Date in the early 1990s, and first published "A New Database Design Principle" in the July 1994 issue of Database Programming and Design and reprinted several times.

Key takeaways

Principle of orthogonal design belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Principle of orthogonal design to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Principle of orthogonal design from memory before moving on to harder problems.

Reference excerpt

The principle of orthogonal design (abbreviated POOD) was developed by database researchers David McGoveran and Christopher J. Date in the early 1990s, and first published "A New Database Design Principle" in the July 1994 issue of Database Programming and Design and reprinted several times. It is the second of the two principles of database design, which seek to prevent databases from being too complicated or redundant, the first principle being the principle of full normalization (POFN). Simply put, it says that no two relations in a relational database should be defined in such a way that they can represent the same facts. As with database normalization, POOD serves to eliminate uncontrolled storage redundancy and expressive ambiguity, especially useful for applying updates to virtual relations (e.g., view (database)). Although simple in concept, POOD is frequently misunderstood and the formal expression of POOD continues to be refined. The principle is a restatement of the requirement that a database is a minimum cover set of the relational algebra. The relational algebra allows data duplication in the relations that are the elements of the algebra. One of the efficiency requirements of a database is that there be no data duplication. This requirement is met by the minimum cover set of the relational algebra.

Sources Database Debunkings: The Principle of Orthogonal Design, Part I, by D. McGoveran and C. J. Date [1] Database Debunkings: The Principle of Orthogonal Design, Part II, by D. McGoveran and C. J. Date [2]

Worked examples

Example 1 — a first encounter with Principle of orthogonal design

Start with the simplest possible case. Write down what Principle of orthogonal design claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Principle of orthogonal design before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Principle of orthogonal design ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Principle of orthogonal design

In research: Principle of orthogonal design appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Principle of orthogonal design in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Principle of orthogonal design is common in secondary-school and first-year university syllabi. It links to neighbouring topics Database theory, so understanding it makes those chapters shorter.
In everyday life: Look for Principle of orthogonal design outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Principle of orthogonal design in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Principle of orthogonal design means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Principle of orthogonal design out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Principle of orthogonal design in simple terms?

Why does Principle of orthogonal design matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Principle of orthogonal design?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Principle of orthogonal design.