1 Introduction
1.1 Writing
Note The purpose of writing this data requirement is pointed out that the expected reader.
1.2 background
Description:
a. The name of the software system is developed;
b. b. List the task of this item, developers, users, and computing stations (centers) or computer network systems that will run the software.
1.3 definition
List the definitions of the specimen used in this document and the original phrase of the foreign letter group word.
1.4 Reference
List the relevant references, such as:
a. The approved planning task book or contract of the project, the approval of the superior authority;
b. Other issued documents belonging to this project;
c. Files, information, information, including the software development standards you want. List the titles, file numbers, and publishing units of these files. Note the source of these file materials can be obtained.
2 logical description of data
Data can be divided into dynamic data and static data for logical descriptions of data. The so-called static data refers to the data mainly used in the operation, and they do not change in a long period of time, generally not changed with operation. The so-called dynamic data, including all data to occur in operation and data to be input, output in operation. When describing, each data element should be logically divided into several groups, such as functions, source data, or more appropriate logical packets for their applications. A name (including abbreviation and code), define (or physical meaning), name, value domain, format, and type, etc. of each data element.
2.1 static data
All static data elements as control or reference are listed.
2.2 Dynamic Limit Data
List dynamically input data elements (including data to be changed in conventional operations or online operations).
2.3 Dynamic Output Data
List the dynamic output data elements (including data to be changed in conventional operations or online operations).
2.4 Internally generated data
List the internal generation data provided to the maintenance debug person from the user or development unit.
2.5 data conventions
Describe the restrictions on the data requirements. Limit the restrictions on the data requirements for further expansion or use, the maximum value of the number of capacity, text, record, and data elements of the data. It is clear that it is clearly pointed out for the determination of design and development.
3 data collection
3.1 requirements and range
According to the logical grouping of data elements, the requirements and scope of data acquisition, indicate the acquisition method of the data, indicating that the launch of data acquisition work is the user or the developer. The specific content includes:
a. Enter the source of data, for example a single operator, data input station, professional data input company or a group of groups;
b. Data input (referring to the media and hard devices used in the data input processing system). If only the input of the specified input point is legal, you must explain it;
c. The recipient illustrates the recipient of the output data;
d. The form of output data and the device lists the form and hard devices of the output data. Whether the recipient will receive the received data, a set of characters, one frame, or a alarm bell on the CRT, or a electrical pulse provided by the switching coil, or common medium such as disk, tape, perforated card, etc. It should be specified in detail;
e. The range of the data value is given the scope of the legal value of each data element;
f. Quantity gave the metric unit, the incremental step size, the scalar of zero point, and the like. In the case where the data is non-digital, the form and the meaning of each legitimate value are given;
g. Update and processing frequency gives the frequency of updates and processing of the input data. If the input of the data is random, the average value of the frequency of the update processing should be given, or some other metric of the change.
3.2 Location of losers
Explain the predetermined bearer of data input work. If the input data is related to a certain interface software, the source of the interface software should be explained.
3.3 Preprocessing
Special provisions for data collection and pretreatment processes, including data formats suitable for applications, predetermined data communication media, and time requirements for input. For data volume required to be analog conversion or digital conversion processing, the related information such as the conversion method and the conversion factor is to be given to the software system.
3.4 impact
Note These data requirements may have the impact of equipment, software, users, and development units, such as requiring user units to add a mechanism.
