How To Write General Design And Detailed Design Documents

The part that should be included in the general layout and detailed design:

(1) demand: generally described in product language, which can copy products. Requirement document The part of story list;

(2) noun interpretation (optional): students in non related fields need to see some conceptual properties that need to be known in advance.

(3) design goal It is divided into functional objectives and performance objectives. Functional objectives are generally technical descriptions of product requirements, and performance objectives are based on the performance of product data. Generally speaking, the new service must have a performance target, and the performance target may affect the design plan.

In addition to the parts that should be included, the general design generally includes:

(1) system architecture: in general, there will be a simple architectural diagram and a brief description of the architecture with text.

(2) module introduction: if there are many modules in the schema, we need to briefly introduce the functions of each module.

(3) design and compromise: design and compromise are the most important parts of the overall design.

(4) potential risks (optional);

When designing the output, many of the plans are still uncertain and need to be confirmed at the design review meeting.

The overall design is focused on "compromise". After the overall design review is completed, all the plans should be confirmed at this time, and the detailed design of each module should be exported.

Detailed design is focused on "detail":

(1) summary of the overall design conclusions (optional): a general summary of the conclusions reached in the overall design is given to illustrate the implementation of these conclusions.

(2) interaction process: brief interaction can be explained by text, and complex interaction suggestions are illustrated by flow charts, interaction diagrams or other graphics.

(3) database design: should this be set up in general or in detail?

(4) interface form: with database + interface + process, other students can get the detailed documents, and they can basically get it done.

(5) other details: for example, formula;

After theoretically exporting the detailed design, whoever has obtained the detailed document can complete the project.

Practice sharing:

I. big picture

(1) large scale system or complex process, its frame composition or flowchart will be very large, often much larger than that of A4 paper or word. At this time, it is not appropriate to paste graphics directly in word and paste it. It is suggested that the map be placed on Wiki and directly linked to the document.

(2) we must store the source files of VISO or other graphics, otherwise we will repaint them in the future.

Two, design and compromise

(1) design and compromise are the most important contents of the general layout.

(2) after the review, we should not only know the conclusion of the mail, but also update it in the general layout, explaining which plan we have decided on and why we use it. According to our experience, it is a mystery for me to take over other modules, projects, get the code and documents, and design the plan for me.

(3) sometimes, because of the scheduling or other reasons, it is not always necessary to adopt the best design plan.

(4) finally, designing trade-offs is a good opportunity for Self Justification: because of project progress or historical problems, I have to take a design like this and stop scolding me.

Three, performance objectives

The performance target is new. Module document An essential part of a lot of projects, which has a greater impact on performance, must also be written for performance objectives. Performance generally includes the following parts:

(1) average daily request: generally from the assessment of product personnel;

(2) average QPS: daily average request divided by 4W seconds, why 4W seconds, 24 hours to 86400 seconds, user active time for the day, 2 seconds to 4W seconds;

(3) peak QPS: generally it can be calculated at 2~4 times of QPS;

Internet Co, the product iteration block, the project cycle is long, basically no "document" said, but in fact, writing the document is very helpful for the future maintenance of the system and project.