CompTIA Data+ DA0-002 (V2) Practice Question

The correct answer is GUID/UUID. A Globally Unique Identifier (GUID) or Universally Unique Identifier (UUID) is a 128-bit number designed to be unique across different systems and databases. Its primary purpose is to allow for decentralized generation of identifiers that are, for all practical purposes, guaranteed to be unique, making it the ideal solution for preventing key collisions when consolidating data from multiple sources.

• An Integer is incorrect because using an auto-incrementing integer is the source of the problem described in the scenario.
• A Composite Key is a plausible but less optimal solution. While combining the original key with a source system identifier would create uniqueness, it results in a more complex key structure that is harder to manage and join on compared to a single GUID/UUID column.
• Datetime is incorrect because a timestamp is not guaranteed to be unique. In a high-volume system, multiple records could be created at the exact same time, leading to collisions.