基于web機(jī)票預(yù)定信息系統(tǒng)設(shè)計(jì)與實(shí)現(xiàn)本科生畢業(yè)設(shè)計(jì)論文-資料下載頁(yè)
2025-08-06 08:54本頁(yè)面
【正文】 ion System database is the various ponent closely together and how to bine the key. （3）Database design, information systems development and the building of an important ponent part.（4）Database design personnel should possess the skills and knowledge : knowledge of basic database design and database technology。 puter science knowledge and the basis for program design methodologies and techniques。 software engineering principles and methods。 Application fields of knowledge. 2, the database design features Database construction is the hardware, software and dry conditions, the bination of technology, the management of 0907, based on 1212 data. database design and application systems should be designed bination :Structure (data) design : Design Framework database or database structure。 Practices (processing) design : design applications, such as transaction processing. Traditional software engineering neglected the application of semantic data analysis and abstract, As long as it is possible to postpone the data structure of the early design decisions to the database design and modeling data model research methods punished, ignored the behavior of the design.3, the basic database design steps Database design process is divided into six phases :（1）. Requirements Analysis stageAccurate understanding and analysis of user requirements (including data processing). Needs analysis phase of the whole design process is based on the most difficult and timeconsuming step. （2）. Structural design concept stage Database Design is the whole key to user needs through prehensive, induction and abstract, formation of a specific DBMS independent of the conceptual model. （3）. Logic design stagesconceptual structure will be converted into a DBMS supported by the data model, its optimization.（4）. Physical database design stageLogical data model for the selection of the most suitable application of the physical structure (including storage structure and access methods).（5）. Database Implementation periodthe use of information provided by the DBMS language, tools and host language, According to the logic design and physical design, build up a database, pilation and debugging application procedures and organization of data warehousing, and to conduct the test run.（6）.Database operation and maintenance phasesdatabase application system after trial operation will be able to mence after the formal operation. In the database system operation process must continue to conduct its evaluation, adjustment and change. Design features : in the process of designing the database design and database design data processing closely bine these two aspects need demand analysis, abstract, design, realization of the various stages in the same time, crossreferencing and plement each other, and to improve both the design. 4, the database model levels the process of forming(1). Demand analysis phases : Comprehensive all user application needs.(2). conceptual design stages : formation of independent machines feature independent of the various DBMS products conceptual model (ER) of.(3). logic design stage : First ER plan into specific database products to support the data model, such as the relational model, create database logic model。 according to the user requirements, safety considerations, in the basic table on the basis of the establishment of the necessary View (View), formed outside the data model.(4). Physical design stage : DBMS features and disposal needs, physical storage arrangements for the establishment of the index, forming a database model.5, database design skills1. Database design before (needs analysis phase)1) understanding the customer39。s needs, asked users how to think about the future changes in demand. Allow customers to explain their needs, and with the continued development, they often ask clients to ensure their needs are still in the development39。s objectives.2) understand the businesses at a later development stage save a lot of time. 3) to input and the definition database table and field needs (input), we should first examine the existing design or have the statements, inquiries and View (output) decision to support the export of what is necessary tables and fields.4) the creation of a data dictionary and ER chart : ER diagrams and data dictionary allows anyone to understand database clear how people from the database access to data. ER plans to table shows the relationship between useful, and the data dictionary is illustrated by the use of each field, and any possible presence of Alias. SQL expressions of the documentation of this is entirely necessary.5) the standard definition of the object named norms : database naming various objects must be standardized.2. Table and field design (database logic design)Table design principles Standardization and Normalization : standardization of data contribute to the elimination of the database data redundancy. There are several standardized forms, However, Third Normal Form (3NF) is usually considered in terms of performance and scalability and data integrity to achieve the best balance. In simple terms, pliance with the standard three NF database table design principles are : One Fact in One Place is a table only includes its own basic attributes, When they had not themselves have the attributes required when deposition. The relationship between the table of foreign bond link. It is characterized by the following : a group of specialized storage table through bond linking the associated data. Indeed, for reasons of efficiency, the table does not standardized sometimes necessary.Design principles field Each table should have added three useful field : dRecordCreationDate. In VB default is Now (), and the SQL Server sRecordCreator. in SQL Server default NOT NULL DEFAULT nRecordVersi on record version labeling。 contribute to the accurate description of the record appeared null da
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