Ch.4 Part 2

Question 1

What are the relational database design rules?

Answer 1

Entity integrity: Primary key cannot be null(empty)

Referential integrity: If a foreign key is null, it must have a value corresponds to the primary key or another table

Question 2

Relational data tables

Answer 2

For data to relate from one table to another table, the data tables must have a specific structure using primary keys which uniquely identifies information for that table

Question 3

Example of primary keys in relational data tables

Answer 3

Primary key for sales table is sales table invoice number and primary key for customer table is customer number