In databases, a surrogate key is an artificially created primary key that is used to uniquely identify a record in a table. Surrogate keys are usually integers and have no real-world meaning or value, but are created solely for the purpose of identifying records in a table.
A surrogate key is often used when a natural key, which is a key that has real-world meaning, cannot be used as a primary key or when a composite key, which is a key made up of two or more columns, becomes too complex or unwieldy. In such cases, a surrogate key is created as a simple, non-composite key that can be easily used to identify records in the table.
Surrogate keys are useful in many scenarios, including when you need to create a new record before a natural key is available, or when you need to uniquely identify records across multiple tables. Surrogate keys can also improve performance by making it easier to create and update records, since they don't require as much processing power as composite keys or natural keys.
One common type of surrogate key is an auto-incrementing integer, where a new unique value is generated automatically for each new record in the table. This can simplify the process of creating and updating records, since you don't need to manually assign a unique value to each record.
Surrogate keys are a common approach used in many database management systems, and are often used in conjunction with other types of keys, such as foreign keys, to ensure data integrity and consistency across multiple tables.
