UML to Work

The ESU University wants to computerize their registration system

1. The Registrar sets up the curriculum for a semester
2. One course may have multiple course offerings
3. Students select 4 primary courses and 2 alternate courses
4. Once a student registers for a semester, the billing system is notified so the student may be billed for the semester
5. Students may use the system to add/drop courses for a period of time after registration
6. Professors use the system to receive their course offering rosters
7. Users of the registration system are assigned passwords which are used at logon validation

What are levels of Normalization

The first three levels in normalising a database are:
First Normal Form (1NF): There should be no repeating groups in a table.
Second Normal Form (2NF): No non-key fields may depend on a portion of the primary key.
Third Normal From (3FN): No fields may depend on other non-key fields. In other words, each field in a record should contain information about the entity that is defined by the primary key.

Database design Keys

Primary key enforce entity integrity by uniquely identifying entity instances

Foreign key enforce referential integrity by completing an association between two entities

Candidate key is an attribute that can be uniquely used to identify a database record (Ex. Social security number in employee table)

Composite Key is combination of more than one attribute which uniquely identify a database record

Unique key is an attribute which can be used to identify a single record

What are Basic Constructs of E-R Model

Entity
Entity is a data object about which information is to be collected. (ex.EMPLOYEE, PROJECT, INVOICE).
An entity is analogous to a table in the relational model.
Entities are classified as independent or dependent
An independent entity is one that does not rely on another for identification.
A dependent entity is one that relies on another for identification.

What is Normalization

The process of structuring data to minimize duplication and inconsistencies
The process usually involves breaking down a single table into two or more tables and defining relationships between those tables.

What is Entity-Relationship design Model

The ER model is a conceptual data model that views the real world as entities and relationships

Difference between Logical and Physical Data Modeling

Logical Data Model:
Entity
Attribute
Primary Key
Alternate Key
Inversion Key Entry
Rule
Relationship

Physical Data Model
Table
Column
Primary Key Constraint
Unique Constraint or Unique Index
Non Unique Index
Check Constraint, Default Value
Foreign Key

Data Modeling Development Cycle

Phase-1 : Gathering Business Requirements
Phase-2: Conceptual Data Modeling (CDM).
Phase-3: Logical Data Modeling (LDM).
Phase 4: Physical Data Modeling (PDM).
Phase 5: DB design

UML Concepts

The UML may be used to:

1. Display the boundary of a system & its major functions using use cases and actors
2. Illustrate use case realizations with interaction diagrams
3. Represent a static structure of a system using class diagrams
4. Model the behavior of objects with state transition diagrams
5. Reveal the physical implementation architecture with component & deployment diagrams
6. Extend your functionality with stereotypes

What is the UML?

• UML stands for Unified Modeling Language

• The UML combines the best of the best from

1. Data Modeling concepts (Entity Relationship Diagrams)
2. Business Modeling (work flow)
3. Object Modeling
4. Component Modeling

• The UML is the standard language for visualizing, specifying, constructing, and documenting the artifacts of a software-intensive system

• It can be used with all processes, throughout the development life cycle, and across different implementation technologies

E-R Model data relation ship

Relationship
represents real world associations among one or more entities

What is Data Modeling in Software

A data model is a conceptual representation of the data structure that are required by a database.

The data model focuses on what data is required and how it should be organized rather than what operations will be performed on the data