1.9 Primary Keys

Question 1

primary key

Answer 1

A primary key is a column, or group of columns, used to identify a row.

Question 2

simple primary key

Answer 2

A simple primary key consists of a single column.

Question 3

composite primary key

Answer 3

A composite primary key consists of multiple columns.

Question 4

Minimal

Answer 4

Minimal. All primary key columns are necessary for uniqueness. When any column is removed, the resulting simple or composite column is no longer unique.

Question 5

PRIMARY KEY

Answer 5

The PRIMARY KEY constraint in a CREATE TABLE statement names the table’s primary key. The PRIMARY KEY constraint ensures that a column or group of columns is always unique and non-null.

Question 6

auto-increment column

Answer 6

An auto-increment column is a numeric column that is assigned an automatically incrementing value when a new row is inserted.

Question 7

AUTO_INCREMENT

Answer 7

Keyword in the create table statement that defines an auto-increment column. ColumnName INT AUTO_INCREMENT