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Database Management System

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Database Management System
DBMS Functionality
Main Characteristics of the Database Approach
Instances and Schemas
Data independence
The Entity-Relationship Model
Database Users
Advantages of Using the Database Approach

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Database Management System

  1. 1. TRINITY INSTITUTE OF PROFESSIONAL STUDIES Sector – 9, Dwarka Institutional Area, New Delhi-75 Affiliated to Institution of G.G.S.IP.U, Delhi BCA DBMS BCA 108 DBMS Basics Keywords: Data, Database,DBMS
  2. 2. TRINITY INSTITUTE OF PROFESSIONAL STUDIES Sector – 9, Dwarka Institutional Area, New Delhi-75 Database Management System (DBMS) • Database Management System (DBMS): A software system used to create and maintain database. • Database System: The DBMS software having data . Sometimes, the applications are also included.
  3. 3. TRINITY INSTITUTE OF PROFESSIONAL STUDIES Sector – 9, Dwarka Institutional Area, New Delhi-75 DBMS Functionality • Define a database : in terms of data types, structures and constraints • Construct or Load the Database on a secondary storage medium • Manipulating the database : querying, generating reports, insertions, deletions and modifications to its content • Concurrent Processing and Sharing by a set of users and programs – yet, keeping all data valid and consistent
  4. 4. TRINITY INSTITUTE OF PROFESSIONAL STUDIES Sector – 9, Dwarka Institutional Area, New Delhi-75 Main Characteristics of the Database Approach • Self-describing nature of a database system: A DBMS catalog stores the description of the database. The description is called meta-data). This allows the DBMS software to work with different databases. • Insulation between programs and data: Called program-data independence. Allows changing data storage structures and operations without having to change the DBMS access programs.
  5. 5. TRINITY INSTITUTE OF PROFESSIONAL STUDIES Sector – 9, Dwarka Institutional Area, New Delhi-75 Main Characteristics of the Database Approach • Data Abstraction: A data model is used to hide storage details and present the users with a conceptual view of the database. • Support of multiple views of the data: Each user may see a different view of the database, which describes only the data of interest to that user. • Sharing of data and multiuser transaction processing :
  6. 6. TRINITY INSTITUTE OF PROFESSIONAL STUDIES Sector – 9, Dwarka Institutional Area, New Delhi-75 Instances and Schemas • Schema – overall description of the database • ex: cust_id : string; cust_name : string; cust_street : string; cust_city : string; • 2 Types of schema : – Physical schema: database design at the physical level – Logical schema: database design at the logical level • Instance – the actual content of the database at a particular point in time
  7. 7. TRINITY INSTITUTE OF PROFESSIONAL STUDIES Sector – 9, Dwarka Institutional Area, New Delhi-75 Data independence • Physical Data Independence – the ability to modify the physical schema without changing the logical schema • Logical Data Independence- the ability to modify the logical schema without changing the external view
  8. 8. TRINITY INSTITUTE OF PROFESSIONAL STUDIES Sector – 9, Dwarka Institutional Area, New Delhi-75 The Entity-Relationship Model • It is collection of entities and relationships – Entity: real life “object” in the enterprise – Relationship: an association among several entities
  9. 9. TRINITY INSTITUTE OF PROFESSIONAL STUDIES Sector – 9, Dwarka Institutional Area, New Delhi-75 Database Users Actors on the scene – Database administrators(DBA): responsible for authorizing access to the database, for co-ordinating and monitoring its use. • Casual : access database occasionally when needed • Naïve or Parametric : they know little about Dbms and databases. • Sophisticated : these include business analysts, scientists, engineers, others thoroughly familiar with the system capabilities..
  10. 10. TRINITY INSTITUTE OF PROFESSIONAL STUDIES Sector – 9, Dwarka Institutional Area, New Delhi-75 Advantages of Using the Database Approach • Controlling redundancy in data storage and in development and maintenence efforts. • Sharing of data among multiple users. • Restricting unauthorized access to data. • Providing persistent storage for program Objects (in Object-oriented DBMS’s – • Providing Storage Structures for efficient Query Processing

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