, Database Systems: Design, Implementation & Management 12e Chapter 10
2026/2027 – Q&A; Study Guide & Practice Questions
Verified Q&A; | Transaction Management & Concurrency Control | Latest 2026/2027 | 100% Unique Questions - No Duplicates
Stuvia-Ready Premium | Original Practice Questions For Study Purposes | Aligned to Coronel & Morris 12e
, 1. What is a transaction and ACID properties per Chapter 10?
A. Transaction is always two queries
B. Transaction is single logical unit of work that must be entirely completed or aborted; ACID: Atomicity all or nothing,
Consistency moves DB valid state to valid, Isolation concurrent transactions don't interfere, Durability committed persists
despite failure
C. ACID only for NoSQL
D. Atomicity means partial commit
CORRECT: B | TOPIC: Transaction Definition ACID
Rationale: ACID is foundation reliability. Atomicity via undo/redo logs, Consistency constraints, Isolation via locks, Durability via
write-ahead log.
2. Difference between atomicity and consistency?
A. Same concept
B. Consistency allows invalid
C. Atomicity allows partial
D. Atomicity all or nothing execution, Consistency ensures DB remains in valid state respecting constraints triggers referential
integrity before and after transaction
CORRECT: D | TOPIC: Atomicity vs Consistency
Rationale: Atomicity via transaction management, consistency via constraints and application logic. Both needed.
3. Transaction states in Chapter 10?
A. Only active and committed
B. Active, Partially Committed, Failed, Aborted, Committed. Active executing, Partially Committed after final statement but
before commit, Committed successful, Failed cannot proceed, Aborted rolled back
C. Committed then Failed
D. No states
CORRECT: B | TOPIC: Transaction State Diagram
Rationale: State diagram: Active -> Partially Committed -> Committed OR Active -> Failed -> Aborted. Checkpoint.
4. Lost update problem example?
A. Normal behavior
B. Only in NoSQL
C. Lost update never happens
D. T1 and T2 read same value 100, T1 adds 10 ->110, T2 adds 20 reading original 100 ->120, final 120 not 130, update of T1
lost, occurs with no locks
CORRECT: D | TOPIC: Concurrency Problems Lost Update
Rationale: Lost update classic concurrency anomaly. Solution locking, timestamping, optimistic.
5. Dirty read dirty dependency?
A. Reading committed data
B. Transaction T1 reads data written by T2 that has not committed yet, if T2 aborts T1 read invalid dirty data, violates isolation
C. Always allowed
D. Good practice
CORRECT: B | TOPIC: Uncommitted Dependency Dirty Read
Rationale: Dirty read is uncommitted dependency. Second problem after lost update. Prevented by no read of uncommitted, strict
2PL.
6. Nonrepeatable read vs phantom read?
A. Same
B. Nonrepeatable read T1 reads same row twice and gets different values because T2 updated and committed between reads,
Inconsistent analysis similar sum average errors, Phantom read T1 reads set of rows twice different number because T2
inserted/deleted
C. Phantom same as dirty
D. Nonrepeatable impossible
CORRECT: D | TOPIC: Inconsistent Analysis Nonrepeatable Read
Rationale: Nonrepeatable read affects row values, phantom affects set cardinality. Both violate repeatable reads.
7. What is serializable schedule and why important?
A. Any schedule is serializable
2026/2027 – Q&A; Study Guide & Practice Questions
Verified Q&A; | Transaction Management & Concurrency Control | Latest 2026/2027 | 100% Unique Questions - No Duplicates
Stuvia-Ready Premium | Original Practice Questions For Study Purposes | Aligned to Coronel & Morris 12e
, 1. What is a transaction and ACID properties per Chapter 10?
A. Transaction is always two queries
B. Transaction is single logical unit of work that must be entirely completed or aborted; ACID: Atomicity all or nothing,
Consistency moves DB valid state to valid, Isolation concurrent transactions don't interfere, Durability committed persists
despite failure
C. ACID only for NoSQL
D. Atomicity means partial commit
CORRECT: B | TOPIC: Transaction Definition ACID
Rationale: ACID is foundation reliability. Atomicity via undo/redo logs, Consistency constraints, Isolation via locks, Durability via
write-ahead log.
2. Difference between atomicity and consistency?
A. Same concept
B. Consistency allows invalid
C. Atomicity allows partial
D. Atomicity all or nothing execution, Consistency ensures DB remains in valid state respecting constraints triggers referential
integrity before and after transaction
CORRECT: D | TOPIC: Atomicity vs Consistency
Rationale: Atomicity via transaction management, consistency via constraints and application logic. Both needed.
3. Transaction states in Chapter 10?
A. Only active and committed
B. Active, Partially Committed, Failed, Aborted, Committed. Active executing, Partially Committed after final statement but
before commit, Committed successful, Failed cannot proceed, Aborted rolled back
C. Committed then Failed
D. No states
CORRECT: B | TOPIC: Transaction State Diagram
Rationale: State diagram: Active -> Partially Committed -> Committed OR Active -> Failed -> Aborted. Checkpoint.
4. Lost update problem example?
A. Normal behavior
B. Only in NoSQL
C. Lost update never happens
D. T1 and T2 read same value 100, T1 adds 10 ->110, T2 adds 20 reading original 100 ->120, final 120 not 130, update of T1
lost, occurs with no locks
CORRECT: D | TOPIC: Concurrency Problems Lost Update
Rationale: Lost update classic concurrency anomaly. Solution locking, timestamping, optimistic.
5. Dirty read dirty dependency?
A. Reading committed data
B. Transaction T1 reads data written by T2 that has not committed yet, if T2 aborts T1 read invalid dirty data, violates isolation
C. Always allowed
D. Good practice
CORRECT: B | TOPIC: Uncommitted Dependency Dirty Read
Rationale: Dirty read is uncommitted dependency. Second problem after lost update. Prevented by no read of uncommitted, strict
2PL.
6. Nonrepeatable read vs phantom read?
A. Same
B. Nonrepeatable read T1 reads same row twice and gets different values because T2 updated and committed between reads,
Inconsistent analysis similar sum average errors, Phantom read T1 reads set of rows twice different number because T2
inserted/deleted
C. Phantom same as dirty
D. Nonrepeatable impossible
CORRECT: D | TOPIC: Inconsistent Analysis Nonrepeatable Read
Rationale: Nonrepeatable read affects row values, phantom affects set cardinality. Both violate repeatable reads.
7. What is serializable schedule and why important?
A. Any schedule is serializable
