Final answer:
True, a primary key uniquely identifies each row in a table and must contain unique values without any NULL entries. It can be a single column or a composite of columns, and it's crucial for maintaining data integrity in database management.
Step-by-step explanation:
True, a primary key is indeed any key that uniquely identifies each row in a database table. Its main purpose is to ensure that every record can be uniquely distinguished from all others. A primary key must contain unique values, and it cannot contain NULL values. In practice, this could be a single column or a combination of columns for composite keys.
For example, in a student database, the student ID could serve as a primary key as it is unique to each student. In the case of a book database, an ISBN number (International Standard Book Number) could be used as a primary key because it's unique to each book edition.
Understanding the concept of primary keys is crucial for database management and design, as they are fundamental to relationships between tables and data integrity. When you design a table, you must designate a primary key to ensure that each record remains unique, thus preserving the reliability of the data contained within the database.