Intermediate LevelSQL & MySQL
What is the difference between READ (Shared) Locks and WRITE (Exclusive) Locks?
❓ Interview Prompt: Compare Table Locks: `READ` (Shared lock - multiple concurrent readers, zero writers) vs `WRITE` (Exclusive lock - single writer, zero readers).
Database engines manage data access concurrency using Shared and Exclusive locks:
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'READ' Lock (Shared Lock): Multiple transactions can hold concurrent READ locks on the same resource to read data simultaneously. Writers are blocked.
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'WRITE' Lock (Exclusive Lock): Only ONE transaction can hold a WRITE lock. All concurrent readers and writers are blocked until the lock is released.
Code Implementation Example
sql
-- Explicitly acquiring shared and exclusive table locks in MySQL
LOCK TABLES orders READ, inventory WRITE;
-- Execute operations...
UNLOCK TABLES;💡Acquiring explicit READ and WRITE table locks in MySQL.
🎯 Interview Key Takeaway
Understand that READ locks allow concurrent readers, while WRITE locks block all other readers and writers.
#SQL#Locks#Shared Lock#Exclusive Lock#Intermediate
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