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DBMS Topics

Hub Unit 1 — Introduction to DBMS & Entity-Relationship Model Advantages and Disadvantages of DBMS Aggregation Characteristics of DBMS Data Independence Data Models Database Users and Administrators DBMS Languages ER Diagrams Entity-Relationship ER Model Introduction to DBMS Keys in DBMS Relationships and Cardinality Schema and Instance Specialization and Generalization Unit 1 Summary — Introduction to DBMS & ER Model Three-Level Architecture ANSI/SPARC Architecture Weak Entity Set Unit 2 — Relational Model & SQL Constraints in SQL Cursors DCL and TCL Commands DDL Commands DML Commands Domain Relational Calculus DRC Functions and Stored Procedures Joins in SQL Nested Queries Subqueries Relational Algebra Relational Calculus Relational Model SQL Introduction Unit 2 Summary — Relational Model & SQL Triggers in SQL Tuple Relational Calculus TRC Views in SQL Armstrong's Axioms & Closure of Attributes Boyce-Codd Normal Form BCNF Closure of Attributes Dependency Preservation Fifth Normal Form 5NF First Normal Form 1NF Fourth Normal Form 4NF Functional Dependency Lossless Decomposition Multivalued Dependency Normal Forms — Overview Normalization — Introduction Second Normal Form 2NF Unit 3 Summary — Normalization Third Normal Form 3NF Unit 4 — Transaction Management & Concurrency Control ACID Properties Checkpoints Concurrency Control & Serializability Deadlock in DBMS Lock-Based Protocols & Two-Phase Locking Log-Based Recovery Recovery System Serializability Shadow Paging Unit 4 Summary — Transaction Management & Concurrency Control Timestamp-Based Protocol Transaction Management Transaction States Two-Phase Locking 2PL Unit 5 — Storage & Indexing B+ Tree B-Tree Cost Estimation Dynamic Hashing File Organization Hashing Techniques Indexing — Introduction Multi-Level Indexing Query Optimization Query Processing Single-Level Indexing Static Hashing Unit 5 Summary — Storage & Indexing Unit 6 — Advanced Topics in DBMS Big Data and DBMS Cloud Database Data Mining Data Warehouse Database Security Distributed Database Distributed Query Processing Distributed DBMS Architecture, Fragmentation & Replication MongoDB — Introduction NoSQL Database Replication in Distributed Databases Unit 6 Summary — Advanced Topics in DBMS Viva Voce — DBMS Important Viva Questions — DBMS Interview Questions — DBMS Viva Answers — DBMS DBMS Multiple Choice Questions MCQs DBMS Lab Programs

Unit 2 — Relational Model & SQL

Last Updated : 21 May, 2026

This unit covers the formal foundations of relational databases and the Structured Query Language SQL. Starting from the mathematical basis of relational algebra and calc

Unit 2130 words2 headingsTables included

Unit Overview

This unit covers the formal foundations of relational databases and the Structured Query Language (SQL). Starting from the mathematical basis of relational algebra and calculus, it builds to practical SQL commands used in real systems.

Topics Covered

Topic	Description
Relational Model	Tables, tuples, attributes, integrity rules
Relational Algebra	Formal procedural query language
Relational Calculus	Declarative query specification
SQL Introduction	History and overview
DDL Commands	CREATE, ALTER, DROP
DML Commands	SELECT, INSERT, UPDATE, DELETE
DCL & TCL	GRANT, REVOKE, COMMIT, ROLLBACK
SQL Constraints	PK, FK, CHECK, UNIQUE, NOT NULL
Joins	INNER, OUTER, CROSS, SELF
Nested Queries	Subqueries, EXISTS, IN
Views	Virtual tables and use cases
Triggers	Event-driven automatic actions
Functions & Procedures	Reusable PL/SQL routines
Cursors	Row-by-row processing

Exam Focus

Revise definitions, diagrams, examples, and short-answer points for Unit 2 — Relational Model & SQL.

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 2 — relational model & sql

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Unit 2Unit 2 Summary — Relational Model & SQL Unit 2Relational ModelThe relational model was proposed by Dr. E.F. Codd of IBM in 1970 in his landmark paper "A Relational Model of Data for Large Shared Data Banks." It is based on the mathe Unit 2Domain Relational Calculus DRCDomain Relational Calculus DRC is a non-procedural query language where variables range over individual attribute values domains rather than entire tuples.Unit 2Relational AlgebraRelational algebra is a formal, procedural query language for the relational model. It provides the theoretical foundation for SQL. Operations take one or two relations a Unit 2Relational CalculusRelational calculus is a non-procedural declarative query language for the relational model. Unlike relational algebra which specifies HOW to retrieve data, relational ca Unit 2Tuple Relational Calculus TRCTuple Relational Calculus TRC is a non-procedural query language where each query is expressed as:

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