Answer
A phantom read occurs when repeating a condition query returns a changed set of rows because another transaction inserted, deleted, or updated matching rows. • The anomaly concerns the set selected by a predicate. • Isolation implementations differ in how they prevent it. • Serializable execution protects broader transaction rules and may require retries.
💡 SQL Example
BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
Result
BEGIN
⚡ Quick Revision
A phantom read changes the row set matching a repeated condition.