science

Negative database

Negative database 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 Negative database rather than just read about it. In short: In database security, a negative database is a database that saves attributes that cannot be associated with a certain entry. A negative database is a kind of database that contains huge amount of data consisting of simulating data.

Key takeaways

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

Reference excerpt

In database security, a negative database is a database that saves attributes that cannot be associated with a certain entry. A negative database is a kind of database that contains huge amount of data consisting of simulating data. When anyone tries to get access to such databases both the actual and the negative data sets will be retrieved even if they steal the entire database. For example, instead of storing just the personal details you store personal details that members don't have. Negative databases can avoid inappropriate queries and inferences. They also support allowable operations. Under this scenario, it is desirable that the database support only the allowable queries while protecting the privacy of individual records, say from inspection by an insider. Collection of negative data has been referred to as "negative sousveillance":

"Negative databases (Esponda, 2006), is the keeping records which if stolen do not reveal the identity of individuals. Negative databases achieve this by storing the complement of the set of what is being tracked. Essentially the database shows what isn’t of concern. Extending his approach the negative intelligence gatherer would seek to understand what websites, infrastructure systems, environmental sensors or documents have become unavailable. The negative sousveillance concept then is to record, track, or infer what isn’t there."

Worked examples

Example 1 — a first encounter with Negative database

Start with the simplest possible case. Write down what Negative database 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 Negative database 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 Negative database 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 Negative database

In research: Negative database 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 Negative database 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: Negative database is common in secondary-school and first-year university syllabi. It links to neighbouring topics Database security, Database stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Negative database 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 Negative database in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Negative database 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 Negative database out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Negative database in simple terms?

Why does Negative database 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 Negative database?

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 Negative database.