DBMS Topics
HubUnit 1 — Introduction to DBMS & Entity-Relationship ModelAdvantages and Disadvantages of DBMSAggregationCharacteristics of DBMSData IndependenceData ModelsDatabase Users and AdministratorsDBMS LanguagesER DiagramsEntity-Relationship ER ModelIntroduction to DBMSKeys in DBMSRelationships and CardinalitySchema and InstanceSpecialization and GeneralizationUnit 1 Summary — Introduction to DBMS & ER ModelThree-Level Architecture ANSI/SPARC ArchitectureWeak Entity SetUnit 2 — Relational Model & SQLConstraints in SQLCursorsDCL and TCL CommandsDDL CommandsDML CommandsDomain Relational Calculus DRCFunctions and Stored ProceduresJoins in SQLNested Queries SubqueriesRelational AlgebraRelational CalculusRelational ModelSQL IntroductionUnit 2 Summary — Relational Model & SQLTriggers in SQLTuple Relational Calculus TRCViews in SQLArmstrong's Axioms & Closure of AttributesBoyce-Codd Normal Form BCNFClosure of AttributesDependency PreservationFifth Normal Form 5NFFirst Normal Form 1NFFourth Normal Form 4NFFunctional DependencyLossless DecompositionMultivalued DependencyNormal Forms — OverviewNormalization — IntroductionSecond Normal Form 2NFUnit 3 Summary — NormalizationThird Normal Form 3NFUnit 4 — Transaction Management & Concurrency ControlACID PropertiesCheckpointsConcurrency Control & SerializabilityDeadlock in DBMSLock-Based Protocols & Two-Phase LockingLog-Based RecoveryRecovery SystemSerializabilityShadow PagingUnit 4 Summary — Transaction Management & Concurrency ControlTimestamp-Based ProtocolTransaction ManagementTransaction StatesTwo-Phase Locking 2PLUnit 5 — Storage & IndexingB+ TreeB-TreeCost EstimationDynamic HashingFile OrganizationHashing TechniquesIndexing — IntroductionMulti-Level IndexingQuery OptimizationQuery ProcessingSingle-Level IndexingStatic HashingUnit 5 Summary — Storage & IndexingUnit 6 — Advanced Topics in DBMSBig Data and DBMSCloud DatabaseData MiningData WarehouseDatabase SecurityDistributed DatabaseDistributed Query ProcessingDistributed DBMS Architecture, Fragmentation & ReplicationMongoDB — IntroductionNoSQL DatabaseReplication in Distributed DatabasesUnit 6 Summary — Advanced Topics in DBMSViva Voce — DBMSImportant Viva Questions — DBMSInterview Questions — DBMSViva Answers — DBMSDBMS Multiple Choice Questions MCQsDBMS Lab Programs
Unit 4 — Transaction Management & Concurrency Control
Last Updated : 21 May, 2026
This unit covers how databases maintain data integrity when multiple operations execute simultaneously or when system failures occur. Transactions are the fundamental uni
Unit 4190 words3 headingsTables included
Unit Overview
This unit covers how databases maintain data integrity when multiple operations execute simultaneously or when system failures occur. Transactions are the fundamental unit of work, and concurrency control ensures safe parallel execution.
Topics Covered
| Topic | Description |
|---|---|
| Transaction Management | Definition, properties, lifecycle |
| Transaction States | Active, Partially Committed, Committed, Failed, Aborted |
| ACID Properties | Atomicity, Consistency, Isolation, Durability |
| Concurrency Control | Problems with concurrent access |
| Serializability | Conflict and view serializability |
| Lock-Based Protocols | Shared and exclusive locks |
| Two-Phase Locking | Growing and shrinking phases |
| Deadlock in DBMS | Detection, prevention, avoidance |
| Timestamp Protocol | Timestamp ordering for concurrency |
| Recovery System | Types of failures and recovery categories |
| Log-Based Recovery | Write-ahead logging, undo/redo |
| Checkpoints | Reducing recovery time |
| Shadow Paging | Alternative recovery technique |
Learning Objectives
- Define a transaction and explain ACID properties with examples
- Draw and explain the transaction state diagram
- Identify and resolve concurrency problems (dirty read, lost update, etc.)
- Explain and apply two-phase locking
- Detect and handle deadlocks using wait-for graphs
- Explain log-based recovery with undo/redo operations
- Describe checkpointing and shadow paging techniques
Exam Focus
Revise definitions, diagrams, examples, and short-answer points for Unit 4 — Transaction Management & Concurrency Control.
Interview Use
Prepare one clear explanation, one practical example, and one common mistake for this DBMS topic.
Search Terms
dbms, database management system, database notes, sql, unit, unit 4 — transaction management & concurrency control
Related DBMS Topics
Continue learning this concept
Unit 4Unit 4 Summary — Transaction Management & Concurrency ControlUnit 4Concurrency Control & SerializabilityConcurrency control is the mechanism that ensures correct results when multiple transactions execute simultaneously, without interfering with each other.Unit 4Transaction ManagementA transaction is a logical unit of work consisting of one or more database operations reads/writes that must be executed as a single indivisible unit. Either ALL operatioUnit 4Transaction StatesA transaction passes through a series of well-defined states during its lifetime. The DBMS tracks the state of every transaction to manage concurrency and recovery correcUnit 4ACID PropertiesACID is an acronym for the four key properties that every database transaction must satisfy to ensure data validity even in cases of errors, power failures, and concurrenUnit 4CheckpointsA checkpoint is a snapshot mechanism where the DBMS periodically writes all dirty modified buffer pages to disk and records the state of active transactions in the log.