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This article will explain in detail how to set up a database for you. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

There are six steps to establish the database: 1, demand analysis; 2, conceptual structure design; 3, logical structure design; 4, physical structure design; 5, database implementation; 6, database operation and maintenance.

There are six steps to establishing a database:

According to the method of standard design, considering the whole development process of database and its application system, the database design is divided into the following six stages.

In the process of database design, requirement analysis and conceptual design can be carried out independently of any database management system, and logical design and physical design are closely related to the selected DAMS.

1. Requirements analysis phase (usually from top to bottom)

To design the database, we must first accurately understand and analyze the needs of users (including data and processing). Requirements analysis is the basis of the whole design process, and it is also the most difficult and time-consuming step. Whether the demand analysis is sufficient and accurate or not determines the speed and quality of building the database building on it. Poor requirements analysis will lead to a rework of the entire database design.

The task of requirements analysis is to fully understand the working situation of the original system, clarify the various needs of users, and then determine the new system functions through a detailed investigation of the objects to be dealt with in the real world, and then determine the new system functions on this basis. the new system also has to fully consider possible future expansion and changes, not only according to the current application requirements.

The focus of the survey is on data and processing. Meet information requirements, processing requirements, security and integrity requirements.

The SA (Structured Analysis) structural analysis method is commonly used in the analysis method. The SA method starts with the top-level system organization structure and uses the top-down, layer-by-layer decomposition method to analyze the system.

Data flow diagram expresses the relationship between data and processing process. In SA method, the processing logic of processing process is often described with the help of decision table or decision tree. When the processing function is decomposed step by step, the data in the system is also decomposed step by step, forming several levels of data flow graph. The data in the system is described with the help of data dictionary (data dictionary,DD). Data dictionary is a collection of all kinds of data descriptions in the system. Data dictionary usually includes five stages: data item, data structure, data flow, data storage, and processing process.

2. Conceptual structure design stage (usually bottom-up)

Conceptual structure design is the key of the whole database design. It forms a conceptual model independent of concrete DBMS by synthesizing, summarizing and abstracting user requirements.

There are usually four ways to design a conceptual structure:

From the top down. That is, first define the framework of the global conceptual structure, and then refine it step by step.

From the bottom up. That is, we first define the conceptual structure of each local application, and then integrate them to get the global conceptual structure.

Gradually expand. First, define the most important core conceptual structure, and then expand outward, gradually generate other conceptual structures in a snowball way, until the overall conceptual structure.

Mixed strategy. That is, the combination of top-down and bottom-up.

3. Logical structure design stage (Emurr diagram)

Logical structure design is to transform the conceptual structure into a data model supported by a DBMS and optimize it.

At this stage, the Emurr diagram is very important. We need to learn the attributes defined by each entity to draw the overall Emurr diagram.

There are mainly three kinds of conflicts between Emurr graphs: attribute conflict, naming conflict, and structure conflict.

The problem to be solved in the transformation from Emurr diagram to relational model is how to transform the relationship between entity and entity into relational schema, and how to determine the attributes and codes of these relational schemas.

4. Physical design stage

Physical design is to select a physical structure (including storage structure and access method) that is most suitable for the application environment for the logical data structure model.

First of all, it is necessary to analyze the running transactions in detail to obtain the parameters needed to select the physical database design. Secondly, it is necessary to fully understand the internal characteristics of the RDBMS used, especially the access methods and storage structure provided by the system.

There are three common access methods: 1. At present, the index method is mainly the B+ tree index method. two。 Clustering method (Clustering) method. 3. It's the HASH method.

5. Database implementation phase

In the database implementation stage, the designer operates the database language (such as sql) and its host language provided by DBMS, establishes the database according to the results of logical design and physical design, compiles and debugs the application, organizes the data into the database, and carries on the trial operation.

6. Database operation and maintenance phase

After trial operation, the database application system can be put into formal operation, and it must be constantly evaluated, adjusted and modified during the operation of the database system.

On how to establish a database to share here, I hope that the above content can be of some help to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

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