Business Flow Chart/Data Dictionary/system flow chart

A business flow chart is a chart that describes the business relationship, operation sequence, and management information flow between units and personnel in the system. It helps analysts find out the non-Confluence direction in the business flow, it is a physical model.
The business flow chart mainly describes the business trend. For example, for a patient, the patient first needs to register, then goes to the doctor to open the medicine, then obtains the medicine from the pharmacy, and then goes home.
The business flow chart describes the complete business flow, which is centered on the business processing process. Generally, there is no data concept.
A data flow chart is a main tool that comprehensively describes the logic model of an information system. It can use a few symbols to comprehensively reflect the flow, processing, and storage of information in the system, A data flow chart is a logical model.
The data flow describes the data trend. We will continue to use the patient as an example. At this time, we will mainly figure the tables required by the patient registration system, how to store the data, and the tables used by doctors to see a doctor, how to save the data.
Data flowcharts further remove material elements, collect relevant information, and use computers for information management to prepare for the next analysis.
A Data Flow Diagram describes the processing and data, without highlighting the sequence of processes. It focuses on processing, data flow, and data storage.
A Data Flow chart describes how to transmit data between sub-blocks. A data dictionary is equivalent to a comparison table in a database. It maps the symbols you know with those in the system!
The data dictionary records the data of the entire project. For example, format, field name in the table in the database, number of windows...
The system flow chart is a description of the information processing system that will be built in the future when the system analyst is in the system architecture phase, or is exposed to the actual system. This description is relatively simple and complete, involving processing components used in the future system, such as disks, displays, user input, and Sequential Representation of processing processes, the standard system flow chart should have 10 types of elements. For details, refer to the national standard. Of course, the system flow chart can also be used to represent the components and order involved in the existing information system processing process.
A data flow chart is a process in which system analysts extract a logical model after a comprehensive system analysis is built in the system design phase. It focuses more on data processing in the process, the physical process and physical distribution of specific data processing are ignored. In fact, there are only four standard elements in the initial data flow chart! Storage of entities, processes, data streams, and data. In addition, the data stream analysis process is constantly improving the actual process, from the top-layer data flow diagram to the layered data flow diagram and data stream, the process type is also gradually increased, until the final data dictionary and underlying data flow graph are formed. You can refer to the description in the software engineering textbook for the data flowchart. Unfortunately, the flowchart in the textbook does not comply with national standards, but the general meaning is the same.
The above two expressions are feasible during project design, depending on the type and scale of the project. If the project is a general engineering application of MIS, process-based processing, the DFD analysis method is very useful. First, design the system flow chart and design the system data flow chart, then there is database design, etc. If it is a development product-level project, haha, it may not be very suitable.

# Software Engineering