Normalized bubble chart for Data in the Instructors

Normalized bubble chart for Data in the Instructor’s View Instructor Standard fee Course + Date Participant Organizatio n Text book Title Grade

Normalized bubble chart View 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

Bubble Chart integrating the instructor’s view and the course promoter’s view High degree Instructor university year Course + Date Text book Overall rating fee Participant Grade Title Organizatio n City zip Prospect Title stree t

Bubble Chart integrating the instructor’s view and the course promoter’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 Systems Physical 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 & Procedures It includes procedures for ◦ Analysing ◦ Implementing ◦ And operating system ◦ Designing and documenting program ◦ Training users

Databases ◦ ◦ ◦ 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

Software There 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 Systems The 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 System Data 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 System Data 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 First name Address datatype is text and size is 15 characters dtatype is text and size is 10 characters copy from

Database Management Systems Data 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 systems Query Languages ◦ SQL ◦ Fourth Generation languages Binary Assembly COBOL FORTRAN PASCAL

People: The Most important Element The primary concerns of Users User views of Data & information The Role of Top Management The 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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