Difference between Primary Key and Unique Key in Oracle Databases

In Oracle databases, a primary key and a unique key are both used to enforce uniqueness in columns, but they serve different purposes.

Primary Key:

A primary key is a column or a set of columns that uniquely identify each record in a table. It enforces uniqueness and ensures that each record in the table has a unique identifier. A primary key column cannot have NULL values.

Unique Key:

A unique key is also used to enforce uniqueness, but it allows for one NULL value. Unlike a primary key, a unique key can be used to enforce uniqueness on columns that are not designated as the primary key of the table.

Overall, primary keys are used to uniquely identify records in a table, while unique keys are used to enforce uniqueness on specific columns.