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Feb 2001 CSS/416: Module U1 Workshop 2
1
CSS/416
Data DesignAnd
Information Retrieval
Workshop 2
Feb 2001 CSS/416: Module U1 Workshop 2
2
Workshop 2 Outline Learning Team Presentations Preview of Workshop 3
Chapter 16The Hierarchical and Network
Data Models
David M. Kroenke
Database Processing
© 2000 Prentice Hall
Feb 2001 CSS/416: Module U1 Workshop 2
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DL/I
“Language for processing a database, implemented in the hierarchical database, IMS (Information Management System) from IBM”
Page 453
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DL/I Hierarchical Terms Field “smallest unit of data” Segment “groups of fields; nodes
of the tree structure” Data base record “a collection
of related segments; a particular tree structure”
Data base “composed of database records”
Page 453
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DL/I Hierarchical Terms Data base description “how
data base records are defined; set of assembly-language macro instructions”
Root “first segment” Sequence field “one field in each
segment used to order the occurrences of a given type”
Page 453
Description of Data Base
Page 455Figure 16-7 © 2000 Prentice Hall
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DL/I Hierarchical Terms Physical data base record (PDBR)
“describes the data as it exists in data storage”
Logical data base record (LDBR) “describes the data as they appear to the application program”
Page 457
Hierarchies
Page 456Figure 16-8
© 2000 Prentice Hall
DL/1 Data Manipulation Commands
Page 462Figure 16-11 © 2000 Prentice Hall
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CODASYL DBTG Model Conference on Data Systems Languages Data Base Task Group
CODASYL also developed standards for COBOL
Complex and Incohesive
Page 462
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CODASYL DBTG Terms Schema “complete logical view of the
database” Subschema “view of the database as
it appears to an application program” Data structure description “maps
schema records, fields, and relationships to physical storage”
Page 462
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CODASYL DBTG Terms User working area “contains
database and control data for a particular user”
Run-unit “the execution of a program by one of the users”
Page 463
CODASYL DBTG Program/Data View Relationships
Page 463Figure 16-12 © 2000 Prentice Hall
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CODASYL DBTG Terms Data-item “a field that
corresponds to an attribute (column)”
Record “a collection of data-items”
Set “a one-to-many relationship”
Page 463
CODASYL DBTG Record Types
Page 464Figure 16-13 © 2000 Prentice Hall
Two-Owner Record in Different Sets
Page 466Figure 16-18 © 2000 Prentice Hall
Summary of Set Characteristics
Page 467Figure 16-19 © 2000 Prentice Hall
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CODASYL DBTG Data Manipulation Language
FIND, GET FIND, MODIFY FIND, ERASE
Page 470
Chapter 17Object-Oriented
Database Processing
David M. Kroenke
Database Processing
© 2000 Prentice Hall
Feb 2001 CSS/416: Module U1 Workshop 2
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Object-Oriented Programming
OOP; a way of designing and coding programs which views programs as sets of data structures that have both data elements and program instructions
Page 483
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OOP Terminology Encapsulated complete in itself Encapsulated structure an OOP
object that has both attributes (properties) and methods
Interface external appearance of an object
Page 484
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OOP Terminology Implementation “the encapsulated
internals of an object” Inheritance “automatically
assuming the attributes and methods of another object at a higher class”
Polymorphism “situation in which one name can be used to invoke different functions”
Page 484
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OOP Terminology Object Class “the logical structure
of an object (name, attributes, methods)”
Object Class Library “a group of object classes”
Objects “instances of objects” Transient vs. Persistent
“volatile vs. permanent”Page 485
Sample Objects, Methods, and Attributes
Page 486Figure 17-2 © 2000 Prentice Hall
Sample Object Data Structures
Page 489Figure 17-4 © 2000 Prentice Hall
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Swizzling
“The process of transforming permanent identifiers into in-memory addresses”
Page 489
Tasks for Object Persistence
Page 489Figure 17-5 © 2000 Prentice Hall
Application Development Work for Object Persistence
Page 492Figure 17-8 © 2000 Prentice Hall
ODBMS Advantages and Disadvantages
Page 493Figure 17-9 © 2000 Prentice Hall
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ODBMS Standards SQL3 “an extension to SQL92 that
includes support for OODBMS” Abstract data type “ADT; user-
defined structure that is equivalent to an OOP object”
Page 495
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ODMG-93
“Object Data Management Group; a consortium of object database vendors and experts that developed a definition of interfaces for object data management products in 1993”
Page 500
Key Elements of the ODMG Object Model
Page 501Figure 17-15 © 2000 Prentice Hall
ODMG Relationship Operations
Page 502Figure 17-16 © 2000 Prentice Hall
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Data Structures
C 102
A 103
D -00 B 100
101
Linked List
(100) (101) (102) (103)
Head
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Data StructuresIndexed
Ames 101
Boyce
103
Jones 102
Smith
100
Smith
Anaheim
Ames
Santa Ana
Jones Irvine
Boyce
Costa Mesa
100
101
102
103
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Data Structures
AE Alex BE Betty
CA Carl D Don
B-treeRoot
BL JI
AI BL CA JI
AI Alice
BL Bill CT Cathy
JI Jill
Value or pointer
