Transaction: Concepts and Concurrency Problems

Introduction

• Speaker: Vishwadeep (Channel Lead and Unacademy Educator)
• Main Topic: Definition of transaction, scheduling, concurrency, and database problems
• Additional Information: Unacademy platform and GATE exam preparation

What is a Transaction?

• Definition: A sequence of multiple read and write operations in a database
• Example: Database read and write operations in train ticket booking

Key Terms

1. Transaction: A logical unit of database

   • Operations: Read and write

2. Commit and Rollback

   • Commit: Permanent change in the database
   • Rollback: Reverting to the last committed state

Transaction Properties (ACID)

1. Atomicity: Transaction completes or nothing at all
2. Consistency: Ability to provide consistent results
3. Isolation: Multiple transactions without impacting each other
4. Durability: Permanent change

Schedule

• Definition: Collection of more than one transaction
• Database Values: Access in the same table and column
• Concurrency: Difference between parallel and concurrent operations

Why is Concurrency Needed?

1. Improved Throughput: More transactions per unit time
2. Reduced Waiting Time: Less waiting time for transactions
3. Resource Utilization: Better resource use

Concurrency Problems

1. Deadlock: Two transactions wait for each other
2. Recoverability Problem: Reading wrong values or data
3. Inconsistent State: Inconsistent results

Upcoming Topics

• Serializability
• Deadlock Handling
• Locking Protocols
• Timestamp and other solutions

Announcement

• 20% Discount Offer: On Unacademy subscriptions
• GATE 24 Batch Start: Starting from October 14, examples and advantages
• Benefits of Unacademy Platform: Live classes, digital notes, test series

Conclusion

• Learning and Guidance: For building a career in the right direction
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