# Mixed Practice: Databases

- **Track:** Cambridge IGCSE™ Computer Science (0478 / 0984) (CAMBRIDGE IGCSE 0478)
- **Module:** Section 9: Relational Databases & SQL
- **Estimated Duration:** 20 minutes
- **Access:** Open Theory (All-Access for Interactive IDE & Autotests)

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## Theory & Conceptual Background

Close your notes and try the mixed questions. Write calculations or a diagram on paper where useful. If you miss an item, explain the misconception and revisit its lesson before trying again.

## Delayed review

Return to these questions after studying another module, rather than only repeating them immediately. Change a value or a condition and predict how the answer changes. Explain one answer aloud without relying on a memorised keyword.

## Written transfer

Choose a practical example from this module and explain the mechanism, one benefit and one limitation. Check that each point refers to the example. Structured automatic checks cannot judge the quality of this explanation; use the lesson's worked examples and a teacher's feedback for that.

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## Interactive Exercises & Autotest Specifications

### Exercise 1: Cumulative Check: Apply earlier ideas (Fill in blank, 30 XP)

**Instructions:**
Work out each answer before submitting. A key must uniquely identify a field or record? Select every field uses which symbol? COUNT or SUM finds the number of records? Highest first uses ASC or DESC?


**Starter Code:**
```text
{"prompt":"Cumulative Check: Apply earlier ideas","template":"1. A key must uniquely identify a field or record? [blank_1]\n2. Select every field uses which symbol? [blank_2]\n3. COUNT or SUM finds the number of records? [blank_3]\n4. Highest first uses ASC or DESC? [blank_4]","blanks":[{"id":"blank_1"},{"id":"blank_2"},{"id":"blank_3"},{"id":"blank_4"}],"word_bank":["record","field","table","*","ALL","COUNT","SUM","DESC","ASC"]}
```