Database Normalisation Questions Medium
A primary key is a column or a set of columns in a database table that uniquely identifies each row in the table. It is used to enforce entity integrity and ensure that there are no duplicate or null values in the key column(s). A primary key is typically chosen from the existing data in the table, such as a natural key derived from the attributes of the entity being represented.
On the other hand, a surrogate key is an artificially created key specifically for the purpose of uniquely identifying each row in a table. It is not derived from the data itself but is generated by the database system, often using an auto-incrementing integer or a globally unique identifier (GUID). Surrogate keys are commonly used in situations where there is no suitable natural key or when the natural key is too long or complex to be efficiently used as a primary key.
The main difference between a primary key and a surrogate key is their origin and purpose. A primary key is derived from the data and represents a meaningful attribute or combination of attributes, while a surrogate key is generated solely for the purpose of identification. Surrogate keys provide a simple and efficient way to uniquely identify rows, especially in complex or large databases, but they do not carry any inherent meaning or significance.