Primary Key A primary key is a special type of index that enforces data integrity and ensures each row's uniqueness. When a primary key is defined on a table, the database management system automatically creates an index on the primary key column(s). This index allows for efficient

An index is a data structure created on top of an existing table within a database. Its purpose is to improve the speed of data retrieval by providing a way to access quickly (fast lookups) the desired data without having to scan the entire table. A real-world example can be