Category Archives: DBMS

Lossless Join and Dependency Preserving Decomposition

Decomposition of a relation is done when a relation in relational model is not in appropriate normal form. Relation R is decomposed into two or more relations if decomposition is lossless join as well as dependency preserving. Lossless Join Decomposition If we decompose a relation R into relations R1 and R2, Decomposition is lossy if… Read More »



See Placement Course for placement preparation, GATE Corner for GATE CS Preparation and Quiz Corner for all Quizzes on GeeksQuiz.

Functional Dependency and Attribute Closure

Functional Dependency A functional dependency A->B in a relation holds if two tuples having same value of attribute A also have same value for attribute B. For Example, in relation STUDENT shown in table 1, Functional Dependencies STUD_NO->STUD_NAME, STUD_NO->STUD_ADDR hold but STUD_NAME->STUD_ADDR do not hold How to find functional dependencies for a relation? Functional Dependencies… Read More »



See Placement Course for placement preparation, GATE Corner for GATE CS Preparation and Quiz Corner for all Quizzes on GeeksQuiz.

DBMS | Anomalies in Relational Model

We strongly recommend to refer below posts as a prerequisite of this. DBMS | Relational Model Introduction and Codd Rules DBMS | Keys in Relational Model (Candidate, Super, Primary, Alternate and Foreign) Anomalies There are different types of anomalies which can occur in referencing and referenced relation which can be discussed as: Insertion anomaly: If… Read More »



See Placement Course for placement preparation, GATE Corner for GATE CS Preparation and Quiz Corner for all Quizzes on GeeksQuiz.

DBMS | Relational Model Introduction and Codd Rules

Terminology Relational Model: Relational model represents data in the form of relations or tables. Relational Schema: Schema represents structure of a relation. e.g.; Relational Schema of STUDENT relation can be represented as: STUDENT (STUD_NO, STUD_NAME, STUD_PHONE, STUD_STATE, STUD_COUNTRY, STUD_AGE) Relational Instance: The set of values present in a relation at a particular instance of time… Read More »



See Placement Course for placement preparation, GATE Corner for GATE CS Preparation and Quiz Corner for all Quizzes on GeeksQuiz.

Database Management System Introduction | Set 2 (3-Tier Architecture)

Database Management System – Introduction | Set 1 DBMS 3-tier Architecture DBMS 3-tier architecture divides the complete system into three inter-related but independent modules as shown in Figure 1.                                                     Figure 1 Physical Level: At physical level, the information about location of database objects in data store is kept. Various users are DBMS… Read More »



See Placement Course for placement preparation, GATE Corner for GATE CS Preparation and Quiz Corner for all Quizzes on GeeksQuiz.

Database Management System – Introduction | Set 1

Important Terminology Database: Database is a collection of inter-related data which helps in efficient retrieval, insertion and deletion of data from database and organizes the data in the form of tables, views, schemas, reports etc. For Example, university database organizes the data about students, faculty, and admin staff etc. which helps in efficient retrieval, insertion and… Read More »



See Placement Course for placement preparation, GATE Corner for GATE CS Preparation and Quiz Corner for all Quizzes on GeeksQuiz.