What are the six steps to create a database?

Six steps to establish a database: 1. Requirements analysis; 2. Conceptual structure design; 3. Logical structure design; 4. Physical structure design; 5. Database implementation; 6. Database operation and maintenance.

Six steps to establish a database:

According to the standardized design method, consider the development of the database and its application system The whole process divides database design into the following six stages

In the database design process, requirements 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 stage (commonly used top-down)

To conduct database design, you must first accurately understand and analyze user needs (including data and processing). Requirements analysis is the foundation of the entire design process and is also the most difficult and time-consuming step. Whether the requirements analysis is sufficient and accurate determines the speed and quality of building a database building on it. If the requirements analysis is not done well, it will cause the entire database design to be reworked and redone.

The task of requirements analysis is to fully understand the working profile of the original system and clarify the various needs of users through detailed investigation of the objects to be processed in the real world, and then determine the new system functions on this basis. The new system also Possible expansions and changes in the future must be fully considered, and not only can the design be based on current application requirements.

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

The commonly used analysis method is SA (Structured Analysis) structured analysis method. The SA method starts from the top-level system organizational structure and analyzes the system in a top-down, layer-by-layer decomposition method.

The data flow diagram expresses the relationship between data and processing. In the SA method, the processing logic of the processing is often described with the help of a decision table or decision tree. While the processing functions are gradually decomposed, the data in the system are also decomposed step by step, forming several levels of data flow diagrams. The data in the system is described with the help of a data dictionary (DD). The data dictionary is a collection of various data descriptions in the system. The data dictionary usually includes five stages: data items, data structure, data flow, data storage, and processing.

2. Conceptual structure design stage (commonly used bottom-up)

Conceptual structure design is the key to the entire database design. It synthesizes, summarizes and Abstract, forming a conceptual model independent of the specific DBMS.

There are usually four types of methods for designing conceptual structures:

Top-down. That is, first define the framework of the global conceptual structure, and then gradually refine it.

Bottom-up. That is, first define the conceptual structure of each local application, and then integrate them to obtain the global conceptual structure.

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

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

3. Logical structure design stage (E-R diagram)

Logical structure design is to convert the conceptual structure into a data model supported by a certain DBMS and will be optimized .

At this stage, the E-R diagram is extremely important. Everyone must learn the attributes defined by each entity to draw the overall E-R diagram.

There are three main types of conflicts between E-R diagrams: attribute conflicts, naming conflicts, and structural conflicts.

The problem to be solved in the conversion of E-R diagram to relational model is how to convert the entity and the connection between entities into relational patterns, and how to determine the attributes and codes of these relational patterns.

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, we must analyze the running transactions in detail to obtain the parameters needed to select the physical database design. Secondly, we must fully understand the internal characteristics of the RDBMS used, especially the access methods and storage structures provided by the system.

There are three types of commonly used access methods: 1. Index method, currently mainly the B-tree index method. 2. Clustering method. 3. It is the HASH method.

5. Database implementation phase

In the database implementation phase, designers operate the database language (such as sql) and its host language provided by the DBMS, based on the logical design and physical design As a result, the database is established, the application is compiled and debugged, the data is organized into the database, and a trial run is carried out.

6. Database operation and maintenance stage

After the database application system has been put into trial operation, it can be put into formal operation. During the operation of the database system, it must be continuously Evaluate, adjust, and revise.

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