The document discusses low level design (LLD) as a component-level design process that provides the internal logical structure of software, facilitating direct code development with minimal debugging. It also covers object-oriented analysis and design (OOAD), UML as a modeling language, and various UML diagrams that represent classes and relationships within a system. Key concepts like association, aggregation, composition, generalization, and specialization are outlined to illustrate relationships between objects.

1. LOW LEVEL DESIGN
(LLD)

2. LOW LEVEL DESIGN
• It’s a component level design process
• It gives the internal logical design of the software being developed
• It defines the class diagrams that has attributes and methods, defining
relationships between them etc
• It helps to develop the code directly with LLD document with minimal debugging
& testing.

3. OOAD
• Object Oriented Analysis & Design
• OOA – Its an investigation of the objects needed to develop a system
• OOD – Collaboration of identified objects during the analysis
• Purpose of OOAD
• identifying the objects,
• recognizing the relationship between them
• make design out of it
• convert it to code using OO languages

4. UML
• Unified Modelling Language
• It’s a pictorial language used to make software blueprints
• It’s used to define, specify, visualize and document the artifacts of a software
systems
• The output from OOAD is the input to UML diagrams

5. COMMON TERMS IN UML
• Class
• Interface
• Collaboration
• Use Case
• Component
• Node
• Dependency
• Association
• Aggregation
• Composition
• Generalization
• Realization

6. UML DIAGRAMS
• Class diagram
• Object diagram
• Use case diagram
• Sequence diagram
• Collaboration diagram
• Activity diagram
• Statechart diagram
• Deployment diagram
• Component diagram

7. CLASS DIAGRAM
• It represents the static view of the module/application
• It defines the attributes and operations of a class
• It can be directly mapped to Object Oriented Programming languages (C++, Java,
Swift, Kotlin etc)
• Class diagram shows a collection of classes, interfaces, associations,
collaborations, and constraints.

8. IMPORTANT CONNECTIONS (CONTD…2)
• Association: It’s a structural relationship that defines how different objects are
connected or associated with each other. It also represents the data flow between
them
Below are treated as special case of association.
• Aggregation: It’s a kind of relationship in which one object can exist independent
of other. (Example: A student in a class)
• Composition: It’s a relationship where the child cannot exist independent of the
parent. (Example: A room in a house)

9. EXAMPLE
Composition Aggregation

10. GENERALIZATION & SPECIALIZATION
• Its a mechanism for combining similar classes of objects into a single, more general class.
• Generalization is Top-Down approach, where as Specialization is Bottom-Up approach

11. IMPORTANT CONNECTIONS

12. REPRESENTATION OF CLASS DIAGRAM

13. Example & Questions