You Are Browsing ‘DBMS’ Category

Posted on Jun 9 2016 - 2:27pm by Preeti
#0

Short Notes on Entity, Attributes, Key   Entity An entity is ‘thing’ or ‘object’ in the real world that is distinguishable from all other objects. Object may be person, place, event etc. Types of Entity Strong Entity: Entities having its own attribute as primary keys are called strong entity. For example, STUDENT has STUDENT_ID as primary key. Hence it is a strong entity. Weak Entity: Entities which cannot form their own attribute as primary key are known weak entities. These entities will derive their primary keys from the...

Short Notes on Schema, Sub-schema, Instances, Data Independence   Schema A schema is plan of the database that give the names of the entities and attributes and the relationships among them. A schema includes the definition of the database name, the record type and the components that make up the records. Alternatively it is defined as a framework into which the values of the data items are fitted. The values fitted into the frame work changes regularly but the format of schema remains the same. The values fitted into the framework...

Posted on Jun 8 2016 - 12:45pm by Preeti
#0

Data Base Management System Architecture (DBMS) DBMS is program or group of programs that work in conjunction with the operating system to create, process, store, retrieve, control and manage the data.The architecture is a framework for describing database concepts and specifying the structure of database system. DBMS architecture is the way in which the data in a...

Data Models/Database Models and their Types   Data Models Underlying structure of the database is called as data model. It is a collection of conceptual tools for describing data, data relationships, data semantics and consistency constraints. Data models define how data is connected to each other and how they are processed and stored inside the system. Types...

Overview of Database Management System (DBMS) Topics covered under Overview of Database Management System: Meaning of Database Management System Characteristics of Database Management System Components of Database Management System   Meaning of DBMS A Database is a collection of related data organized in a way that data can be easily accessed, managed and...