20 min read
Storing Data
Facts must be kept so the library can use them after the person has left the desk.
Why Store Data?
A week later Sophie Walsh returns to the desk. She has forgotten her membership number. She needs to borrow a book.
George remembers that Sophie’s phone starts with 07700, but he cannot recall the rest. Amelia still has the card. She reads 07700 900 123. Sophie confirms it. The loan can go ahead.
If the card had been thrown away, the library would have had to ask Sophie for everything again.
This is why the library stores data. Later is real.
Sophie will come back. A book will go missing. The council will ask again next term. Memory will not hold a growing list of phone numbers. Sticky notes fall off the monitor. A chat message gets buried.
| What the library needs, and when | ||
|---|---|---|
Store First, Use Later
Store first, use later
Not every observation is worth storing. The library stores phones because it will need to call people. It does not store what Sophie was wearing, because that will not help anyone find a book.
Amelia puts Sophie’s card in a box labelled Members. Harry’s card goes in after it. Emily’s follows. The box is clumsy. It already works better than memory.
Practice
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