A Primary Key and a Foreign Key are both essential concepts in database design, but they serve different purposes.
A Primary Key is a unique identifier for each record in a table. It ensures that no two rows in a table have the same value for the primary key column(s).
It must contain unique values and cannot have NULL values. For example, in a Students table, the StudentID might be the primary key to uniquely identify each student.
A Foreign Key, on the other hand, is a column (or set of columns) that creates a relationship between two tables. It refers to the primary key of another table, establishing a link between the records in the two tables. For example, in an Orders table, the CustomerID may be a foreign key that references the CustomerID primary key in the Customers table.
