Google Data Analytics Professional Certification Practice Test

What is the significance of a unique primary key in a database?

1. It allows data sharing between organizations

2. It ensures no duplicate records exist in a table

3. It organizes data into different formats

4. It protects data from unauthorized access

The correct answer is: It ensures no duplicate records exist in a table

A unique primary key is crucial in a database because it ensures that each record in a table is distinct and can be uniquely identified. This prevents duplicate entries, which can lead to data integrity issues, confusion, or errors during data retrieval and analysis. Without a unique primary key, the data could contain multiple identical entries, making it difficult to track and manage individual records. With a guaranteed unique value for each entry, databases can efficiently organize, retrieve, and maintain data integrity, leading to more reliable analytics and reporting. The other options, while relevant to database management, do not directly relate to the specific role of a primary key. For instance, data sharing between organizations is influenced by various factors such as data format compatibility and organization policies, but it is not a direct function of a primary key. Similarly, while data protection is essential, it is addressed through security measures rather than a unique primary key. Lastly, organizing data into different formats pertains to data presentation and transformation rather than the structural integrity provided by primary keys.