Data Flow Diagrams, UML, and Process Specifications
Entities, Data Flows, Processes, and Data Warehouses
Entity: Also known as a source or destination, an entity is used to send or receive data to the system. It is considered to be outside the system described.
Data Flow: Shows the movement of data from one point to another. The arrowhead indicates the destination of the data.
Process: Represents a change of data and their processing. It represents the work to be performed on the system.
Data Warehouse: Represents a data repository, which lets you browse, add, and retrieve data.
Data Flow Diagram Software
Data Flow Diagram Software focuses on the business and its operation. It does not address how the system will be built, but rather describes the events that occur in the business.
Physical Data Flowchart
Physical Data Flowchart: Shows how to implement the system, including software, hardware, and people involved in the system.
Six Reasons to Partition DFD
- User groups in February-March
- Similar tasks sync
- Efficiency
- Consistency of data
- Security
Data Dictionary
Data Dictionary: A reference book with information about the collected data. It is like a document, as it collects data, coordinates specific terms, and confirms what each term means.
Storage of Information and Data
The data warehouse is a collection of data and information larger than the data dictionary. It can store information about the data, the logic of procedures, both screen and report design, etc.
Structured Spanish
When the process involves iteration formulas or structural decisions that are not complex, it is advisable to use Structured Spanish, which is based on formal logic and simple Spanish statements.
Decision Tree
A square indicates an action, and a circle indicates a condition. To draw a decision tree, you must first identify the conditions and actions, and their order and length. Then, begin to build the tree from left to right, taking into account all possible alternatives before moving to the right.
See Process Specification Form on page 328.
UML (Unified Modeling Language)
UML is a standardized set of tools to document the analysis and design of software systems. UML is based on the representation of things, relationships, and diagrams. One of its features is that it is used to represent object-oriented components.
Activity Diagram
An Activity Diagram illustrates the sequence of activities of a process, including sequential activities, parallel activities, and decisions made. It is developed for a use case in order to reflect the different possible scenarios.
Use Case
A Use Case synthesizes an event and has a format similar to the specifications of a process. Each use case defines an activity and its trigger, input, and output.
Structured Spanish
The first type of process specification is based on formal logic and simple sentences in Spanish. It serves as a communication tool with users. Structured Spanish uses sequences, decisions (IF-ELSE), and iterations (DO WHILE).
Logical Data Structure
A Logical Data Structure describes and explains all sorts of information concerning the operation, implementation, business requirements, and approaches.
Physical Data Structure
A Physical Data Structure relates to the operation focused on what the system requires in concrete terms and its implementation, such as entering customer data, creating tickets, etc.
The Six Most Used UML Diagrams
- Use Case Diagram: Describes how to use the system.
- Use Case Scenario: A verbal description of the principal exceptions to the behavior described by the main use case.
- Activity Diagram: Shows the general flow of activities.
- Sequence Diagram: Shows the sequence of activities and class relations.
- Class Diagram: Shows the classes and relations.
- State Chart Diagram: Shows the state transitions.