What type of data or entity is typically used in a database for unique record identification?

A primary key is usually used for unique identification of records in a database. Most often, it is a field with a data type that guarantees uniqueness, such as:

• An integer type with auto-increment (e.g., INT AUTO_INCREMENT in MySQL)
• UUID (Universally Unique Identifier) — a fixed-length string generated by a specific algorithm that ensures uniqueness

Example of using UUID in Java with JPA:

import javax.persistence.*;
import java.util.UUID;

@Entity
public class User {
    @Id
    @GeneratedValue
    private UUID id;

    private String name;

    // getters and setters
}

Thus, the primary key is an entity that uniquely identifies a record in a table.