Software Life Cycle & UML - PDF

# Requirement Analysis Stage - The software life cycle begins with requirements analysis. - The goal is to specify what services the proposed system will provide, to identify any conditions (time constraints, security, and so on) on those services. - Define how the outside world will interact wit...

# Requirement Analysis Stage - The software life cycle begins with requirements analysis. - The goal is to specify what services the proposed system will provide, to identify any conditions (time constraints, security, and so on) on those services. - Define how the outside world will interact with the system. # Figure 7.1 The Software Life Cycle Once software is developed, it enters a cycle of being used and maintained (see figure below) - Development - Use - Maintenance # Figure 7.2 The development phase of the software life cycle - Requirements analysis - Design - Implementation - Testing # Design Stage - Involves creating a plan for the construction of the proposed system. # Implementation Stage - Involves the actual writing of programs, creation of data files, and development of databases. - The software analyst is involved with the entire development process, emphasizing the requirements analysis and design steps. - The programmer is involved with the implementation step, writing programs that implement the design produced by a software analyst. # Testing Stage - **Validation testing** - Confirms that the system meets specifications that the user has predefined, such as producing yearly or monthly reports for the financial situation of a corporation. - **Defect testing** - Find bugs in the code, whether it produces correct results or not. For example, if the code calculates the average salary of the employees. # Software Engineering Methodologies - **Waterfall Model:** Is a model based on the fact the development process was allowed to flow in only one direction. - **Incremental Model:** is a model in which the desired software system is constructed in increments, with the first being a simplified version of the final product with limited functionality. # Tools of the Trade - **Data Flow Diagram:** Is a diagram that shows the way information flows through a process or system. It includes data inputs, processes, data stores, and the various subprocesses. - **Entity-Relationship Diagram:** is a graphical representation showing relationships among people, objects, places, concepts or events within (IT) system. - **Data Dictionary:** is a collection of names, definitions, and attributes about data elements that are being used or captured in a database. # Figure 7.8 A simple dataflow diagram The diagram shows how a *Patient* interacts with a *Hospital*. - *Input* - The *Patient* pays *bills* and *payments*. - *Process Payments* and *Process Bills* have arrows pointing to *Hospital Files* with labels *Patient Records* and *Updated Records*. - *Output* - *Patient Records* go from *Hospital Files* to both *Process Payments* and *Process Bills*. # Entity Relationship Diagram | Relationship | | |---|---| | One to one | Car Company to Car Model | | One to Many | Doctor to Patient | | Many to Many | Student to Subject | # Data Dictionary ## TABLE: Students | COLUMN NAME | TYPE/LENGTH | CONSTRAINTS PK | INDEXED? | |---|---|---|---| | StudentID | CHAR(9) | Yes | Yes | | StudentLastName | CHAR(30) | | Yes | | StudentFirstName | CHAR(20) | | Yes | | Address | CHAR(50) | | Yes | | City | CHAR(30) | | Yes | | State | CHAR(2) | | Yes | | Zip | CHAR(9) | | Yes | ## TABLE: Instructors | COLUMN NAME | TYPE/LENGTH | CONSTRAINTS PK | INDEXED? | |---|---|---|---| | InstructorID | CHAR(6) | Yes | Yes | | InstructorLastName | CHAR(30) | | Yes | | InstructorFirstName | CHAR(20) | | Yes | # Unified Modeling Language (UML) UML is a modeling language in Software engineering developed as a modern collection of tools to provide a standard way to visualize the design of a system. ## Two tools - Use Case Diagram - Class Diagram # Use Case Diagram One of the UML tools developed to capture the image of the proposed system from the user's point of view. - Depicts the proposed system as a large **rectangle** in which: - **Use Cases:** are interactions between the system and its users represented as ovals. - **Actors:** are users of the system represented as **stick figures**. # Figure 7.9 A simple use case diagram - The diagram shows the *Hospital Records System* as a rectangle. - **Actors** include: - *Physician* - *Administrator* - *Nurse* - *Laboratory Technician* - **Use Cases** include: - *Retrieve Medical Record* - *Update Medical Record* - *Retrieve Laboratory Results* - *Update Laboratory Results* - *Retrieve Financial Records* - *Update Financial Records* # Class Diagram - Is a UML type of static structure diagram that describes the structure of a system by showing the system's classes and how they are related. - In a hospital system, physician, nurse, administrator, lab technician are examples of classes. # Figure 7.10 A simple class diagram - The diagram shows relationships between three classes: *Physician*, *Patient*, and *Room*. - *Physician* cares for *Patient* - *Patient* occupies a *Room* - *Patient* hosts a *Room* # Testing - Programs and testing and verification of the programs themselves continue to be a topic of research. - Consequently, many testing methodologies have been developed to improve revealing errors odds in software using limited number of tests. # Documentation - **User Documentation** - Printed book for all customers - On-line help modules - **System Documentation** - Source code - Design documents - **Technical Documentation** - For installing, customizing, updating, etc. # Software Ownership - **Copyright** - Allows a product to be released while retaining ownership of intellectual property ( الملكية الفكرية ). - **Software License** - A legal agreement that grants the user certain permissions without transferring ownership (( براءة الإختراع Patents). - **Patents** - Allows the product developers to release that product and protect ownership rights. - The developer of a product will assert ownership by including a copyright statement.