Cap Theorem easy
In CAP, 'Consistency' is equivalent to:
- A ACID Consistency (the set of valid database state constraints and foreign key relationships).
- B Linearizability (Atomic Consistency), where all system nodes see the exact same data at the same time.
- C Code Consistency (enforcing strict organization-wide coding standards and documentation rules).
- D User Interface Consistency (ensuring all graphical elements and workflows appear uniform to the user).
Answer: B. Linearizability (Atomic Consistency), where all system nodes see the exact same data at the same time.
Consistency in the CAP Theorem is specifically about 'single-copy equivalence' or Linearizability. It means that once a write is acknowledged as successful, any client—regardless of which node they query—must immediately see that new value. This is distinct from ACID consistency, which is about maintaining business rules and data constraints within a single database instance.
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