Normalized bubble chart for Normalized bubble chart for Data in the Instructor’s ViewData in the Instructor’s View

Instructor

Organization

Title

Standard fee

Text bookCourse +

Date

Participant

Grade

Normalized bubble chartNormalized bubble chartView Integration

◦Techniques are available for integrating bubble charts representing individual user views into a composite logical schema of all data items contained in the various views.

◦Detailed description of view integration using bubble charts was given by Martin 1983.

◦The integrated view of the participant’s bubble chart and the instructor’s bubble chart is shown on next slide

Instructor

street

Title

fee

Text

book

Title

year

universityHigh

degree

Course + Date

Prospect

City

zip

Bubble Chart integrating the instructor’s Bubble Chart integrating the instructor’s view and the course promoter’s viewview and the course promoter’s view

Participant

Organization

Overall

rating

Grade

Bubble Chart integrating the Bubble Chart integrating the instructor’s view and the course instructor’s view and the course promoter’s viewpromoter’s view

•If these were the only two views in the module, then this would be one form of logical schema for the database, because it contains all data elements and relationships necessary to support the user view in the module. Furthermore, all necessary redundancies have been eliminated.

•This is the minimal set of data elements and relationships necessary to support the individual user views.

Elements of Database Elements of Database SystemsSystemsPhysical design:

◦ The last step of the database design process is physical design.

◦ Physical design involves converting the software schema into a form

implementable with the organization’s particular hardware, operating system and database management system

Designing navigation path Deciding which records to place in nearby

portions of the storage devices Determining the size of physical records on

storage devices but buffer areas in main memory to hold records

Implementing integrity and security requirements.

Other database Techniques Other database Techniques & Procedures& ProceduresIt includes procedures for

◦Analysing◦Implementing ◦And operating system◦Designing and documenting program◦Training users

DatabasesDatabases Databases are

◦ Integrated◦ Shared collections of files◦ Stored on these devices of the

organizations computer system◦ The way the data is organized and

stored on these devices is referred to as its physical organization

◦ In terms of logical organization. There are many different ways that databases can be organized

SoftwareSoftwareThere are three different kinds of

software involved in most database systems◦ Database management packages◦ Operating system◦ Applications program◦ Most DBM packages use the basic

access methods of the host operating system to perform the necessary input-output operations on the data files themselves

Database Management Database Management SystemsSystemsThe minimum components of a

package that could truly be called a DBMS are◦Data dictionary◦Data definition language◦Query languages◦Data manipulation language◦Report generator language◦Features to support data integrity◦Security, privacy, recovery

Database Management Database Management SystemSystemData Dictionary

◦Is used to maintain standard definitions of all data items within the scope of the DB system

◦The purpose of DD is to enforce standard definitions of the data resources of the organization.

◦Definition includes a precise description of the meaning of a data item name and a precise description of how values of each data item are stored in the computer system.

Database Management Database Management SystemSystemData Dictionary

◦ Functions of DD Maintaining standard user definitions of the

precise meaning of data items and data types Maintaining cross reference list of data items

used Providing standard definitions of data items to

applications programs◦ Examples

Name structure Last name datatype is text and size is 15 characters First name dtatype is text and size is 10 characters

Address copy from Dept code data type is unsigned numeric size is 3 dig

Database Management Database Management SystemsSystemsData Definition Languages

◦Is used to translate the logical schema into a software schema for the DBM package in use

◦Defined by CODASYL committee◦Two languages were defined

DDL SQL

Database Management Database Management systemssystemsQuery Languages

◦SQL◦Fourth Generation languages

Binary Assembly COBOL FORTRAN PASCAL

People: The Most important People: The Most important ElementElementThe primary concerns of UsersUser views of Data & informationThe Role of Top ManagementThe Systems Staff and its Role

◦ The Manager of Information Resource◦ Information Analyst◦ Database Analyst

The User’s View◦ Database application programmer◦ Database Administrator◦ A comment on sharing Role

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