Surrogate keys are unique identifiers used in relational databases to represent individual records or rows within a table. Unlike natural keys, which are derived from the actual data (like a Social Security number or email address), surrogate keys are typically artificial fields, often generated automatically by the database system. These keys can be integers or GUIDs (Globally Unique Identifiers) and are useful for ensuring that each record has a distinct, immutable identifier.
One of the main advantages of using surrogate keys is that they simplify the management of relationships between tables. For example, in a database containing customer and order information, a surrogate key can serve as a foreign key in the orders table to reference the customer table. This means that even if other attributes of a customer change, such as their address or phone number, the surrogate key remains constant, thereby maintaining the integrity of relationships without needing to update multiple records. This leads to cleaner database design and easier data maintenance.
Another important aspect of surrogate keys is that they can enhance performance. Since surrogate keys are simple and typically index efficiently, querying and joining tables using these keys can be faster than using composite or natural keys, which may require additional computation. In scenarios where performance is vital, such as in large-scale data processing or when working with extensive datasets, surrogate keys can contribute positively by making data retrieval quicker and more efficient. Thus, they are a commonly preferred choice in many database design situations.