Lesson 1 · Tables, records and keys

Read a record before counting

Task 1 of 1 · Design and explanation · 0 results checked · 0 explanations saved

Opening your saved work…

Read the idea

A database table groups records with a stated meaning. A column records an attribute. A primary key identifies one record; a row count counts records with that meaning.

A spreadsheet is useful for one person’s small analysis. Shared data needs consistent keys, rules and relationships. An identifier should remain stable when a person’s name changes.

Worked example

shops: number of shop records. orders: number of order records. A primary key must identify one row uniquely.

Your task

A shop table has one row per shop, and an orders table has one row per order. What does COUNT(*) measure in each? Why should two shops not share an id?

Predict or plan before trying

Give me a hint

Use the question’s requirements as your checklist. State an assumption if the wording does not establish a rule.

Compare with a worked answer

shops: number of shop records. orders: number of order records. A primary key must identify one row uniquely.

Using an answer is useful practice. Record what you learned; it does not demonstrate independent mastery.

Explain your evidence

Explain one limitation of putting shops and all of their orders in a single spreadsheet row.

My explanation or revision I would like help with this task

Your instructor can review account-saved work and help requests. Saving does not submit to Canvas.