What is Transaction

Duration: 6 min

This video lesson is available to enrolled students.

Return to /learn/COGNIZANT-PREPARATION/dbms/transaction-management/introduction-acid-properties/asset-what-is-transaction after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. Communication Round: Vocabulary, Subject Verb Agreement (Verb Noun Agreement), Tenses, Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Cloze Test (Cloze Passage), Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Direct and Indirect Speech, Active Passive Voice (Voice), Verbal Analogy (Word Based Analogy), Articles, Preposition, Conjunction, Sentence Construction, English Writing Ability, Communication Assessment
  2. Quantitative Aptitude: Ratio and Proportion (Ratios), Divisibility Rules, Data Interpretation, Mixture and Alligation, Permutation and Combination, Logarithm, Number System, HCF LCM, Speed Time and Distance, Percentage, Average, Powers and Exponents (Surds and Indices), Time and Work, Mensuration and Geometry, Age Problems, Pipe and Cistern, Probability, Profit and Loss, Simple Interest and Compound Interest, Algebra
  3. Analytical and Logical Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Directions (Direction Test), Ranking, Order and Sequence, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Selection Decision Table (Decision Making), Logical Sequence Of Words, Puzzle Solving (Puzzles), Syllogisms, Seating Arrangements, Calendar, Clock, Blood Relations, Cubes & Dices, Venn Diagram, Analytical Reasoning (Counting Figures Reasoning)
  4. Cognizant Gaming Aptitude: Gamified / Game Based Aptitude
  5. Java (Cluster 1): Java
  6. ANSI SQL MySQL (Cluster 1,2,3): SQL
  7. HTML, CSS, JavaScript (Cluster 1,3): HTML, CSS, JavaScript
  8. Python (Cluster 2): Python for Placements by Yash Sir
  9. Cloud Fundamentals (Cluster 2): Emerging Tech Trends
  10. C# (Cluster 3): C#
  11. OOPs: Object Oriented Programming (OOPS)
  12. Technical Assessment (Coding): Coding Questions by Yash Sir, C Programming by Yash Sir, Programming in C++, Pseudo Codes
  13. Data Structures: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  14. DBMS: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, ORDBMS, Database Security & Authorization, Query Processing & Optimization, Enhanced Data Models, Data Warehousing & Mining, Big Data Systems, NoSQL
  15. Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Windows OS, Linux OS, Security, Distributed Systems, Virtual Machines
  16. Computer Networks: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Security, Mobile Technology, Cloud Computing and IoT, Cyber and Info Security
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture introduces the concept of transactions in Database Management Systems (DBMS). The instructor begins by contrasting the operating system's view of atomicity, which operates at the instruction level and allows for partial execution, with the DBMS view where user operations are logical and atomic. Using a fund transfer example (Transaction T1), the video demonstrates how partial execution can lead to data inconsistency. The lesson concludes by formally defining a transaction as a set of logically related instructions bundled together to ensure a logical unit of work is completed without partial failure.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor poses the question 'Why we study transaction?' and contrasts general computation principles with DBMS views. On-screen text explains that in an operating system, the level of atomicity is at the instruction level, meaning partial execution is possible. In contrast, the DBMS view treats user operations as logical work that is always atomic. The instructor introduces Transaction T1, which transfers 100 units from account A to B. A table lists the specific steps: Read(A), A = A-100, Write(A), Read(B), B = B+100, and Write(B). This sets the stage for understanding why higher-level atomicity is needed.

  2. 2:00 – 5:00 02:00-05:00

    The lecture focuses on the consequences of failure during a transaction. The instructor explains that if a failure occurs after Read(B) but before the final write, the system becomes inconsistent because 100 units are debited from account A but not credited to account B. To define consistency, the slide states 'before (A + B) == after (A + B)'. The instructor draws red brackets around the steps in the table to visually group them, emphasizing that these instructions must be treated as a single unit. He explains that to remove the partial execution problem, we must increase the level of atomicity and bundle all instructions of a logical operation into a unit called a transaction.

  3. 5:00 – 6:21 05:00-06:21

    The final segment provides the formal definition of a transaction. The slide text reads: 'So formally 'A transaction is a Set of logically related instructions to perform a logical unit of work'.' The instructor underlines key phrases like 'Set of logically related instructions' and 'logical unit of work'. He reiterates that bundling these instructions removes the partial execution problem seen in general computation. A diagram showing an arrow from A to B is drawn to visualize the transfer. The instructor concludes by reinforcing that transactions are the mechanism used to ensure data integrity and consistency in the face of potential failures.

The video effectively bridges the gap between low-level system operations and high-level database requirements. It establishes that while operating systems handle atomicity at the instruction level, databases require atomicity at the logical operation level to prevent data corruption. By defining a transaction as a bundle of logically related instructions, the lecture provides a clear solution to the problem of partial execution, ensuring that the total value in the system remains constant (consistency) even if failures occur mid-process.

Loading lesson…