Relational databases and SQL

ISC Chapter 6 · Area I · Blueprint I.B

Every ERP, payroll system and web store keeps its data in tables, and every auditor who wants evidence from those tables has to read a query. This chapter opens Brightwater's database: how tables link through keys, the integrity rules that keep the links honest, the data dictionary that explains every field, and why normalization stops the same fact being stored three different ways. Then Sam learns to read SQL like a sentence and, more importantly, to spot the one word in a query that quietly drops half the data. You will not be asked to write long programs on the exam; you will be asked whether a query returns the right records, all of them, and nothing else.

In this chapter

Tables, keys and relationships
Integrity rules that keep the data honest
The data dictionary
Normalization: one fact, one place
Reading SQL
Is the query relevant and complete?

This chapter has 6 lessons, 50 practice MCQs with explanations and 20 simulations, plus flashcards and a recall sheet.

What this chapter covers

Integrity rules, data dictionary and normalization
reading SQL queries for relevance and completeness

Chapter 5: Data storage and the data life cycle · Chapter 7: Data integration and business process models