Killer Interview Question: Explain A Database In Three Sentences

A particularly quirky addition to the killer interview questions collection: Explain a database in three sentences to your eight-year-old nephew.

Kid picture from Shutterstock

This question comes from a compilation of questions once used by Google that were officially deemed too outrageous by the company to use. Many of them fall into the same category as our recent Killer Interview Question candidate: "How many dollars’ worth of hamburgers are sold in China each day?, where how you derive the answer is more important than its accuracy. For instance: "How many piano tuners are there in the entire world?"

For a technical role, we actually think the database question is very reasonable. Being able to explain technology in straightforward terms is an important skill, but one that's not always encouraged for IT roles. A good answer is likely to draw on real-world analogies, though you'd need to pick those carefully (I suspect most eight-year-olds wouldn't know what a phone book was these days).

How would you answer the question?

17 Former Google Interview Questions So Ridiculous Even Google Banned Them [Business Insider]


    "How long can you make a run-on sentence?"
    "Very long! Three times in a row!"
    "Excellent. Next question..."

    A collection of data.

      A structured collection of data

        A collection is structured by its very nature of being a collection?

      The man said three sentences, not three sentences or less.

      With that kind of attention to detail you'll never get this job.

        "This job" being the hypothetical job invented by a blogger on a blog that is less reputable for anything noteworthy than my hat. Okay.jpg.

    It's like how a fridge holds lots of different foods. Except it's for a computer, and instead of food, it has information.

    Imagine a massive room full of people that you can ask a question of at anytime and they will raise their hands to answer. A database is like that but rather than asking people your asking lots of computer files that question and then they reply.

    Its a program that can keep track of your inventory.
    It can also track sales and purchases.
    It can be used to create reports showing performance, or trends.

      Like an 8 year old would understand that...

      Not that I can come up with anything better though!

      Last edited 09/07/14 1:11 pm

      Does it need to be a programme to qualify as a database? Does my shopping list I wrote in the white space of junk mail count as a database? Is you DNA a database?

    To an eight year old?

    It's like a bookshelf, full of all your books.
    You can ask the shelf questions about the books, and it will tell you about the books, like "Which of these books have a Knight in them?", or "Which books can I read in one hour?", or "Which of these books has a Knight AND can be read in an hour?".
    A database is like that, except the books are full of numbers and the questions are all about money.

      This one was good up until the "all about money" part.

        Aw, that was just a bit of humour from someone who works with finance dbs :)


    I had this question at an interview, except that it was a 5 year old and I was just told to be brief. I didn't really like the interviewer and was starting to not want the job at all, so after thinking for a second I just said "A database is like the internet". Apparently this was a good answer because I made it through to the next round.

    I always thought a database was much like a catalogue system that libraries use or used to use. Many thousands or millions of catalogue cards telling you where things are. Like a book on a shelf and then you go there to get and read that book.

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