1. Summary Data Modeling SDLC What is Data Modeling
Application Audience and Services
Entities
Attributes
Relationships
Entity Relationship Diagrams
Conceptual,Logical and Physical Design

2. Example - HW
Let us design a database for a Student Record System, including information about these Entities - Students, Fees, Course, Textbooks,and Department;
Conceptual Design:
Draw the E/R diagram for this database.
Work out the type of relationships among the entities
Logical Design
Work out what are the attributes of each entity and name key for each table
Physical Design
How each data element will be defined in the DDL – names, data types and length with any constraints

3. Conceptual Design : E- R model
Students
Enroll in
Course
pay
has
offers
Fees
has
Textbks
Dept

4. 1. Conceptual Design Draw the E/R diagram for this database.
Work out the type of relationships among the entities
Student……..Course(many to many)
Students……Fees (one to one)
Textbooks….Fees (one to one)
Department…Courses (one to many)
Course………Textbooks (one to many)

5. 2. Logical Design
We now need to work what the attributes of each entity will be and how the entities will be linked together:
Students (Idnumber, Surname, First name, Gender, Sponsor)
Department (DepartmentID, Department name)
Courses (CourseNumber Course Title, Coordinator)
Textbooks (ISBN, Title, Author, Edition)
Fees (FeeCode, Fee Amount)

6. 3. Physical Design Student Idnumber : text(10) not null
Surname : text(30)
First name : text(30)
Gender : text - Alpha(1)
Sponsor : text(30)
Continue with the rest of the tables.
Refer to the Practical Exercise for Defining a table with its fields using the Design Form
Also show the how table linked thru their primary key fields.

7. Using the Database
The process if populating the database by entering data and then querying it to obtain information is known as DML.
Populating: inserting information
File maintenance: saving, retrieving, importing and exporting
Information Retrieval: selecting data
Reporting: creating reports
Sorting: choosing the order the data should be in.
Calculations: putting values from different fields together to create new information.

8. Inserting and updating Database
Using Special Data Entry Forms
Must have tables
Self promoting integrity
Standard and much more presentable
Refer to the practical exercise.

9. Querying the Database
SQL is also used for querying the database which selects information according to specified criteria and can either display the information on screen or output as report.
Basic form of SELECT command is:
SELECT column1, column2, column N
FROM table
WHERE condition is satisfied;

10. Creating reports from database
Results of the query can be saved as a file which can be formatted and then presented as a report.
Report Generators: special tools for creating reports in most DBMS.

11. Types of Reports Detail Reports: List detail fields
Summary Reports: provide information in summary form mainly for executives
Controlled-break reports: Data are grouped into categories
Exception reports: report which match some condition outside the normal limits
Graphs: Graphs and text

12. Who works with Database
Database administrators: oversee and manage the database resources – database, DBMS, and other software etc.
Database Designers:identify data to be stored in the database and for choosing the appropriate structures to represent and store this data. Communicate with all prospective users in order to understand their requirements and to come up with a design that meets these requirements.
End Users: people whose jobs require access to the database querying, updating and generating reports. The database primarily exists for their use.

13. Casual end users: they access the database occasionally, requesting different information each time typically managers.
Naive end-users: Data entry, bank tellers, clerical staff who with main job function revolved constantly querying and updating the database using standard types of query and updates that have been programmed and tested.
Sophisticated end users: include engineers, scientists, business analysts, who thoroughly familiarize themselves with the facilities of the DBMS so as to meet their complex requirements

14. Stand-alone users: they maintain personnel database by using ready-made program packages that provide easy-to-use menu or graphics based interfaces. Ie. Small business people looking after their accounting.

15. System Analysts and Application Programmers: SA Determines the requirements of end-users especially naive end-users and develop specifications for canned transactions to meet those requirements. AP implement these specifications as programs, then they test, debug, document and maintain these canned transactions.
DBMS Designers and Developers: are the people who design and implement the DBMS modules and interfaces as a software package. A DBMS is a complex software system consists of many modules ie. Queries, DDL, DML, Data Access etc. DBMS must interface with OS and other compilers for various programming languages. These personnel typically work with DBMS as ORACLE, FOXBASE, MS ACEESS, RBASE ETC.

16. Tool Developers: Tools are software package that facilitate database system design and use and help improve performance. Tools are optional package that are often purchase separately. Include packages for database design, performance monitoring, prototyping, graphical interfaces etc.
Operators and Maintenance Personnel:
These are the system administration personnel who are responsible for the actual running and maintenance of the hardware and software environment for the database system.

17. List the database personnel involved in each of the following tasks:
Design of the initial database: working out what is required.
Implementing the database design
Testing data into the database and generating reports
Entering data into the database and generating reports
Maintaining the database, looking after the host computer and carrying out regular backups.

18. Answers DBA, USERS, May need system analysts
DBA, Database designers, may need application programmers
DBA, database designers, selected users
Users
Operators