How to write a data dictionary and what does a data dictionary refer to?

Table 0-1: FugoodsType Table Name: FugoodsType

What it means: Cargo type table.

Table structure: the name of the data item.

The type of data item.

The length of the data item.

Whether it's a keyword or not.

Whether it is empty or not. Data item meaning.

Description of the data item. idint

Be. Not. Numbering. Self-incrementing.

namevarchar

Not. Name of the type of goods.

validint

Not. Valid status.

memonvarchar

Be. Remark.

1. The data dictionary is not a traditional paper dictionary, it is a table that comes with some systems, which can query the relevant information of the database, which generally exists in the computer system or other electronic systems for people to check the information and interpretation of the items that they do not understand.

A data dictionary stores information about the data, description, relationship to other data, purpose, and format, and is a database in its own right, storing "data about data items." The Data Dictionary is a guide that provides a "roadmap" for the database, not the "raw data".

In other words, a data dictionary usually refers to a record of data definitions in a database, similar to the data structure of a database, but much richer than the data structure description of the database (Malamud, 1989). In the initial stage of collecting relevant data information and establishing a database, it is necessary to establish a naming convention for data items, and it is necessary to unify the connotation, naming and naming concepts of data of common concern between different departments and individuals.

This process involves data custodians, users, and database developers, and is a process that needs to be repeated many times. This uniform naming convention, along with the accompanying instructions, is the Data Dictionary.

2. The contents of the data dictionary include:

1. Information about all schema objects in the database, such as tables, views, clusters, and indexes;

2. How much space is allocated, how much space is currently used, etc.;

3. The default value of the column;

4. Restrict the integrity of information;

5. The user's name;

6. The permissions granted by users and roles;

7. Audit information accessed or used by users;

8. Other generated database information.

A data dictionary is a directory of records for database and application source data that users can access. An active data dictionary is a data dictionary whose contents can be automatically updated by the DBMS when changes are made to the database or application structure. A passive data dictionary is a data dictionary whose contents must be manually updated when modified.

The data dictionary is drawn as follows:

1.A top-level diagram is an abstract description of the entire system, including only external entities, processes, and data flows.

2.The zero-layer graph cracked and dissolved the original large and early system, increasing the data storage and numbering of processing and external entities.

3.Subgraph, the further decomposition of the zero-layer graph, at this time, it is necessary to give the data storage, external entities, and processing numbers in the subgraph one by one according to the number.

That's how to draw a data dictionary, I hope it can help you.

The data dictionary is as follows:A data dictionary is a definition and description of data items, data structures, data flows, data storage, processing logic, external entities, etc., and its purpose is to make detailed descriptions of each element in a data flow diagram.

The most important role of a data dictionary is as a tool for the analysis phase. The most important use of any dictionary is to query the interpretation of items that are not understood, and in structured analysis, the role of a data dictionary is to define and explain each component of the data flow diagram.

Introduction:

The database data dictionary is not only the center of every database, but it is also very important information for each user. Users can use SQL statements to access database data dictionaries, such as data items, data structures, data flows, data storage, and processing procedures. A data dictionary is an important part of a database.

It holds information about the database and is a set of read-only tables for the user.

A data dictionary is a definition and description of data items, data structures, data flows, data storage, processing logic, external entities, etc., and its purpose is to make detailed descriptions of each element in a data flow diagram. The main function of the data dictionary is to form the logical model of the system together with the data flow diagram. It is difficult to use a data dictionary without a flow graph.

Without a data dictionary, the data flow diagram is not rigorous.

1. The purpose of the data dictionary.

A data dictionary is a collection of descriptions of various types of data; The data dictionary is the main result obtained by conducting detailed data collection and data analysis; Data dictionaries play an important role in database design.

It's important to have a data dictionary at the beginning of the program you're writing. The data dictionary lists the definitions of all the variables you use in the program, as well as some custom descriptions of events and commands. Its definition shall include what the entry is intended to describe and the unit in which it is executed.

When writing a program, compiling a data dictionary may seem unnecessary. But imagine that after some time, you or someone else wants to modify the program, and that's when a data dictionary becomes very useful.

Second, the content of the data dictionary.

data items; Data structure; Data stream; data storage; Processing. A data item is the smallest unit of data, and several data items can form a data structure. A data dictionary describes the logical content of data flow and data storage through the definition of data items and data structures.

1. The concept of data dictionary.

A data dictionary is a record that can be accessed by users to record metadata about databases and applications. Generally, it can be divided into active data dictionaries and passive data dictionaries. An active data dictionary whose contents can be automatically updated when changes are made to the database or application structure.

Passive data dictionaries, whose contents must be manually updated when modified.

2. Users of data dictionaries.

A data dictionary is a description of data, a collection of data objects or item descriptions in a data model. Data dictionaries are beneficial for developers, analysts, algorithm engineers, and other users who need to refer to the data at a faster speed.

When developers use data model programs, a data dictionary can help understand where a data item fits into the structure, what numeric values it might contain, and what it means to represent reality.

For example, when we see academic qualifications, we see that when we need to know the specific meaning, we can know from the dictionary that 01 means elementary school, 02 means junior high school, and 03 means high school.

In short, the goal of the data dictionary is to better integrate and integrate the company's data assets, and it is also a comprehensive combing of the business.

In addition to technical developers, there are analysts, algorithm engineers, risk control strategy engineers, including business operation personnel, and can also query data assets that can be used according to business development to help better expand business. What you can see from the data dictionary is not only the explanation of the data fields, but also the meaning of the business.