[Solved] Consider two transactions running concurrently on a table Products. Transaction 1 reads all rows where price > 100.... If Transaction 1 repeats the read, what phenomenon might it experience? | SQL

SQL - Transactions and Data Integrity

Consider two transactions running concurrently on a table Products. Transaction 1 reads all rows where price > 100. Transaction 2 inserts a new row with price = 150 but has not committed yet. If Transaction 1 repeats the read, what phenomenon might it experience?

APhantom read

BNon-repeatable read

CDirty read

DLost update

Step-by-Step Solution

Solution:

Step 1: Analyze Transaction 2's action
Transaction 2 inserts a new row but has not committed yet, so the data is uncommitted.
Step 2: Understand Transaction 1's repeated read
If Transaction 1 reads this uncommitted row, it is a dirty read because the data is not yet committed.
Final Answer:
Dirty read -> Option C
Quick Check:
Uncommitted insert read = Dirty read [OK]

Quick Trick: Reading uncommitted inserts causes dirty reads [OK]

Common Mistakes:

Assuming phantom read without commit
Confusing non-repeatable read with phantom read
Ignoring commit status of inserted row

Master "Transactions and Data Integrity" in SQL

9 interactive learning modes - each teaches the same concept differently

Learn Why Deep Visual Try Challenge Project Recall Time

More SQL Quizzes

If Transaction 1 repeats the read, what phenomenon might it experience?

Step 1: Analyze Transaction 2's action

Step 2: Understand Transaction 1's repeated read

Final Answer:

Quick Check:

Want More Practice?