Chap1' Introduction to File Structures

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Chap1. Introduction to File
Structures
File Structures by Folk, Zoellick, and Riccardi

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Chapter Objectives

• Introduce the primary design issues
  characterizing file structure design
• Survey the history of file structure design
• Introduce the notions of file structure literacy
  and of a conceptual toolkit for file structure
  design
• Discuss the need for specification of data
  structures, operations and development of
  object-oriented toolkit
• Introduce classes and overloading in C

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Contents

• 1.1 The heart of file structure design
• 1.2 History of file structure design
• 1.3 Conceptual toolkit file structure literacy
• 1.4 Object-Oriented Toolkit
  make file structure usable
• 1.5 Using objects in C

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The Heart of File Structure Design
1.1 The Heart of File Structure Design

• File structure
• representation of data operation for accessing
  data
• Disk vs. RAM
• speed very slower than RAM
• cost enormous capacity at much less cost
  than RAM
• nonvolatile in Disk vs. volatile in RAM
• Good file structure design
• access to all the capacity without spending much
  time waiting for disk
• uniform average access time

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History of file structure design(1)
1.2 History of File Structure Design

• Sequential file
• look at records in order
• AVL tree (Balanced Binary Tree)
• self-adjusting binary tree
• guarantee good access time for data in RAM
• B-tree
• balanced tree structure
• provide fast access to data in file

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History of file structure design(2)
1.2 History of File Structure Design

• B-tree
• variation on B-tree structure
• provide both sequential access and fast-indexed
  access
• Hashing
• transform search key into storage address
• provide fast access to stored data
• Extendible hashing
• approach to hashing that works well with files
  undergoing many changes in size over time

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Taxonomy of File Structures
1.2 History of File Structure Design

• Single-key files
• Index-based (Tree Data Structure)
• Indexed Sequential File -gt B-Tree -gt B-Tree
• Hashing-based (Address Computation)
• Hashing File -gt Extendible Hashing File
• Multi-key files (multidimensional)
• K-D-B tree
• Grid file
• R-tree
• Multimedia Indexing Techniques
• Audio, Image, Video

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Conceptual Toolkit File Structure Literacy
1.3 A Conceptual Toolkit

• Objective of Conceptual toolkit
• Fundamental file concepts
• Generic file operations
• Conceptual tools in this book
• basic tools evolution of basic tools
• basic tools Chapter 2 6
• evolution of basic tools Chapter 7 12
• B-trees, Btrees, hashed indexes, and extensible
  dynamic hashed files

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Object-Oriented Toolkit
Making File Structures Usable
1.4 Object-Oriented Toolkit

• Object-Oriented Toolkit
• making file structures usable requires turning
  conceptual toolkit into collections (classes) of
  data types and operations
• Major problem
• complicated and progressive
• often modified and extended from other classes
  and details of classes become more complex

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Using objects in C(1)
1.5. Using Objects in C

• Features of object in C
• class definition
• data members(attributes) methods
• constructor
• provide a guarantee for initialization of every
  object called in creation time of object
• public, private protected sections
• public label specifies that any users can freely
  access
• private protected label are restrict access

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Using objects in C(2)
1.5. Using Objects in C

• operator overloading
• allows a particular symbol to have more thanone
  meaning
• other features
• inheritance, virtual function, and templates
• explained in later chapters

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Lets Review!!

• 1.1 The heart of file structure design
• 1.2 History of file structure design
• 1.3 Conceptual toolkit file structure literacy
• 1.4 Object-Oriented Toolkit
  make file structure usable
• 1.5 Using objects in C