Data management questions

What is a database application?

Software that helps business users interact with database systems.

Who is responsible for securing the database system?

The database administrator.

What does a query processor do?

Interprets queries, creates a plan to modify the database or retrieve data, and returns query results.

What is the purpose of query optimization?

To ensure the most efficient instructions are executed on the data.

What is metadata in the context of databases?

Data about the database, such as column names and the number of rows in each table.

What is SQL?

Structured Query Language, which includes statements that read and write data, create and delete tables, and administer the database system.

What are relational databases good for?

Databases requiring an accurate record of every transaction, such as banking and airline reservation systems.

What is the difference between a simple primary key and a composite primary key?

A simple primary key consists of a single column, while a composite primary key consists of multiple columns.

Define a foreign key.

A column, or group of columns, that refer to a primary key.

What is referential integrity?

A relational rule that requires foreign key values to be either NULL or match primary key values.

What does the INSERT SQL statement do?

Adds rows to a table.

What is a self-join?

A self-join joins a table to itself.

Explain the HAVING clause.

Used with the GROUP BY clause to filter group results.

What is normalization?

The process of eliminating redundancy by decomposing a table into two or more tables.

What is a materialized view?

A view for which view table data is stored at all times, which must be refreshed when changes occur.

What is the purpose of the ALTER TABLE statement?

To add, delete, or modify columns on an existing table.

What are business rules in the context of databases?

Rules based on business policy and specific to a particular database, ensuring data validity.