Introduction to Database Management Systems
Upcoming SlideShare
Loading in...5
×
 

Introduction to Database Management Systems

on

  • 2,128 views

 

Statistics

Views

Total Views
2,128
Views on SlideShare
2,127
Embed Views
1

Actions

Likes
1
Downloads
159
Comments
0

1 Embed 1

http://www.brijj.com 1

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Introduction to Database Management Systems Introduction to Database Management Systems Presentation Transcript

  • Introduction to Database Management Systems
  • Chapter 1: Introduction
    • Evolution of Database Management Systems
    • Overview of Database Management Systems
    • Database-System Design
  • Database Management System (DBMS)
    • Databases touch all aspects of our lives
    • DBMS:
      • Collection of interrelated data
      • Set of programs to access the data
    • Convenient and efficient processing of data
    • Database Applications
  • Evolution of Database Systems
    • Early days: database applications built on top of file systems
    • Drawbacks of using file systems to store data:
      • Data redundancy and inconsistency
      • Difficulty in accessing data
      • Atomicity of updates
      • Concurrency control
      • Security
      • Data isolation — multiple files and formats
      • Integrity problems
  • Abstraction
    • View level : application programs hide details of data types.
    • Logical level : what data are
    • type employee = record name : string; address : string; s alary : real; end ;
    • Physical level : how data are stored
  • Data Models
    • A collection of tools for describing
      • Data
      • Relationships among data items
      • Semantics of stored data
      • Database constraints
  • Data Models
    • Entity-Relationship model
    • Relational model
    • Other models:
      • Network
      • Hierarchical
      • Object-oriented
      • Semi-structured
  • Database Management Systems
    • Smaller and smaller systems
      • Past: large and expensive DBMS
      • Present: DBMS in most personal computers
    • More and more data stored
      • Past: few MB
      • Present: terabyte (10 12 bytes), petabyte (10 15 bytes)
  • Application Architectures Two-tier architecture Three-tier architecture
  • Database Users
    • Users are differentiated by the way they interact with the system
        • Database Administration : responsible for the structure or schema of the database (DDL), coordinates all activities regarding the database
        • Application programmers – interact with system through DML calls
        • Sophisticated users – form requests in a database query language
        • Naive users – invoke one of the permanent application programs that have been written previously
  • Data Definition Language (DDL)
    • Defines the database schema and constraints
    • DDL compiler  data dictionary
    • Metadata – data about data
  • Data Manipulation Language (DML)
    • Accessing and manipulating the data
      • DML – query language
    • Query Languages
      • Procedural – user specifies what data is required and how to get those data
      • Nonprocedural – user specifies what data is required without specifying how to get those data
    • SQL: nonprocedural query language
  • Transaction Management
    • T ransaction : unit of work to be executed atomically and in isolation from other transactions
    • Transaction-manager : ensures that the database remains in a consistent
      • system failures
      • transaction failures
    • Concurrency-control : interaction among the concurrent transactions to ensure consistency
  • ACID Properties
    • A tomicity: all-or-nothing of the transaction’s effect will take place
    • C onsistency: each transaction leaves the system in a consistent state
    • I solation: each transaction must appear to be executed as if no other transactions are executed at the same time
    • D urability: effect of a transaction must never be lost after the transaction is completed
  • Transaction Processing
    • Logging:
      • Log manager
      • Recovery manager
    • Concurrency control
      • Multiple transactions
      • Locking protocols
    • Deadlock resolution
  • Database System Studies
    • Design of the database
      • What to store, structure, semantics
      • Functionality requirement
      • Trade offs
      • Security
    • Database programming
      • How to express database operations, capability requirements, etc.
    • Database implementation
      • Query, transaction processing, storage, efficiency
  • Next Class: Entity Relationship Model (Cont.)
    • E-R model of real world
      • Entities (objects)
      • Attributes of entities
      • Relationships between entities
    • Widely used for database design
      • E-R model usually converted to design in the relational model