CIW CIW Database Design & SQL

Question 1

What is the purpose of a primary key in a relational database table?

Accepted Answer

To uniquely identify each row in the table

Answer

A primary key is a column or combination of columns whose values uniquely identify every row, preventing duplicate records.

Question 2

Which SQL command is used to retrieve data from a database table?

Accepted Answer

SELECT

Answer

The SELECT statement queries one or more tables and returns a result set matching the specified columns and conditions.

Question 3

What does normalization achieve in database design?

Accepted Answer

Reduces data redundancy and ensures data integrity by organizing tables logically

Answer

Normalization organizes database tables to minimize redundancy and dependency, typically following normal forms (1NF, 2NF, 3NF).

Question 4

What is a foreign key in a relational database?

Accepted Answer

A column that references the primary key of another table to establish a relationship

Answer

A foreign key enforces referential integrity by ensuring that a value in one table matches an existing value in the referenced table's primary key.

Question 5

Which SQL clause is used to filter query results based on a condition?

Accepted Answer

WHERE

Answer

The WHERE clause filters rows before any grouping or aggregation occurs, returning only records that meet the specified condition.

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