“DOK 322 DBMS” Database Design Hacettepe University Department of Information Management DOK 322: Database Management Systems
“DOK 322 DBMS” Y.T. Database Design Hacettepe University Department of Information Management DOK 322: Database Management Systems.
Dec 21, 2015
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“DOK 322 DBMS”
Y.T.
Database Design
Hacettepe University
Department of Information Management
DOK 322: Database Management Systems
“DOK 322 DBMS”
Y.T.
Last Time
File Management Systems vs. DBMSs Advantages and Disadvatages of
DBMS Components of DBMS MS Access 2000 (Lab)
“DOK 322 DBMS”
Y.T.
DBMS Benefits
Minimal Data Redundancy Consistency of Data Integration of Data Sharing of Data Ease of Application Development Uniform Security, Privacy, and Integrity
Controls Data Accessibility and Responsiveness Data Independence Reduced Program Maintenance
“DOK 322 DBMS”
Y.T.
Database Environment
CASE Tools
DBMS
UserInterface
ApplicationPrograms
Repository Database
“DOK 322 DBMS”
Y.T.
Database Components
DBMS===============
Design toolsTable CreationForm CreationQuery CreationReport Creation
Procedural language
compiler (4GL)=============
Run timeForm processorQuery processor
Report WriterLanguage Run time
UserInterface
Applications
ApplicationProgramsDatabase
Database contains:User’s DataMetadataIndexesApplication Metadata
Kroenke, DatabaseProcessing
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Terms and Concepts Database:
– A self-describing collection of integrated records (Kroenke).
– A collection of similar records with relationships between the records. (Rowley)
– A collection of stored operational data used by the application systems of some particular enterprise. (C.J. Date)
“DOK 322 DBMS”
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Terms and Concepts Enterprise
– Organization Entity
– Person, Place, Thing, Event, Concept... Attributes
– Data elements (facts) about some entity– Also sometimes called fields or items or domains
Data values– instances of a particular attribute for a particular
entity
“DOK 322 DBMS”
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Terms and Concepts
Key– an attribute or set of attributes used to
identify or locate records in a file Primary Key
– an attribute or set of attributes that uniquely identifies each record in a file
“DOK 322 DBMS”
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Terms and Concepts
Models– (1) Levels or views of the Database
Conceptual, logical, physical
– (2) DBMS types Relational, Hierarchic, Network, Object-
Oriented, Object-Relational
“DOK 322 DBMS”
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Models (1)
ConceptualModel
LogicalModel
External Model
Conceptual requirements
Conceptual requirements
Conceptual requirements
Conceptual requirements
Application 1
Application 1
Application 2 Application 3 Application 4
Application 2
Application 3
Application 4
External Model
External Model
External Model
Internal Model
“DOK 322 DBMS”
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Database System Life Cycle
Growth,Change, &
Maintenance6
Operations5
Integration4
Design1
Conversion3
PhysicalCreation
2
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Another View of the Life Cycle
Operations5
Conversion3
PhysicalCreation
2Growth, Change
6
Integration4
Design1
“DOK 322 DBMS”
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Database Models
Models(2): DBMS types– Hierarchical– Network– Relational– Object-Oriented
“DOK 322 DBMS”
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Database Data Models
Hierarchical Model– Similar to data structures in programming
languages.Books
(id, title)
Publisher SubjectsAuthors
(first, last)
“DOK 322 DBMS”
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Database Data Models
Network Model– Provides for single entries of data and
navigational “links” through chains of data.
Subjects Books
Authors
Publishers
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Database Data Models
Relational Model– Provides a conceptually simple model for
data as relations (typically considered “tables”) with all data visible.
Book ID Title pubid Author id1 Introductio 2 12 The history 4 23 New stuff ab 3 34 Another title 2 45 And yet more 1 5
pubid pubname1 Harper2 Addison3 Oxford4 Que
Authorid Author name1 Smith2 Wynar3 Jones4 Duncan5 Applegate
Subid Subject1 cataloging2 history3 stuff
Book ID Subid1 22 13 34 24 3
“DOK 322 DBMS”
Y.T.
Database Data Models
Object Oriented Data Model– Encapsulates data and operations as
“Objects”
Books(id, title)
Publisher SubjectsAuthors
(first, last)
“DOK 322 DBMS”
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Database Design Process
ConceptualModel
LogicalModel
External Model
Conceptual requirements
Conceptual requirements
Conceptual requirements
Conceptual requirements
Application 1
Application 1
Application 2 Application 3 Application 4
Application 2
Application 3
Application 4
External Model
External Model
External Model
Internal Model
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Database Design Process Conceptual Requirements
– Systems Analysis Process Examine all of the information sources used in existing
applications Identify the characteristics of each data element
– numeric
– text
– date/time
– etc. Examine the tasks carried out using the information Examine results or reports created using the information
“DOK 322 DBMS”
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Database Design Process
Conceptual Model– Merge the collective needs of all applications– Determine what Entities are being used
Some object about which information is to maintained
– What are the Attributes of those entities? Properties or characteristics of the entity What attributes uniquely identify the entity
– What are the Relationships between entities How the entities interact with each other?
“DOK 322 DBMS”
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Database Design Process
Logical Model– How is each entity and relationship
represented in the Data Model of the DBMS
Hierarchic? Network? Relational? Object-Oriented?
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Database Design Process
Internal Model– Choices of index file structure– Choices of data storage formats– Choices of disk layout
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Database Design Process
External Model– User views of the integrated database – Making the old (or updated) applications
work with the new database design
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Developing a Conceptual Model
Overall view of the database that integrates all the needed information discovered during the requirements analysis.
Elements of the Conceptual Model are represented by diagrams, Entity-Relationship or ER Diagrams, that show the meanings and relationships of those elements independent of any particular database systems or implementation details.
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