作者: wangle 時間: 2025-3-21 21:54
simplifications and pragmatic decisions. The rationale is to try to keep a design simple, but allow room for development as situations change or resources permit..Provides solid design prin978-1-4302-4209-3978-1-4302-4210-9作者: 召集 時間: 2025-3-22 03:49 作者: 表示問 時間: 2025-3-22 05:50
Initial Requirements and Use Cases,o make sure we really understand the problem. This may sound obvious, but it is surprising how often people set about implementing a database before they understand the problem completely. There are two things we need to do: understand what tasks need to be carried out by all the people who will use作者: DEMUR 時間: 2025-3-22 12:18
Learning from the Data Model,first attempt at determining the data that are necessary to support those tasks and formed an initial data model, which we depicted with a class diagram. In this chapter, we look more closely at the data model to see how it can further our understanding of a database system.作者: ENNUI 時間: 2025-3-22 15:11 作者: 揮舞 時間: 2025-3-22 17:50
Generalization and Specialization,might like. We might find that we have some objects for which some of the attributes do not really apply. For example, if we have a class to record information about all the people associated with a company, we might find that some have hourly pay rates while others have annual salaries. In many res作者: 功多汁水 時間: 2025-3-22 22:59 作者: circumvent 時間: 2025-3-23 04:40 作者: 者變 時間: 2025-3-23 06:36 作者: landmark 時間: 2025-3-23 12:01
User Interface,. We specified these requirements in terms of use cases, and most fell into one of two categories: tasks a user would need to carry out to enter data efficiently and tasks for retrieving information in the form of different reports.作者: 消毒 時間: 2025-3-23 15:21
Other Implementations, and the interrelation of the different data items. Chapters 7 through 9 showed how we could take the data model and represent it in a relational database as a set of normalized tables with the relationships implemented by foreign keys. The previous two chapters showed how we could efficiently enter作者: 減少 時間: 2025-3-23 18:01
https://doi.org/10.1007/978-3-031-60149-1ed with two separate classes, for example Lecturers and Students, and then begin to realize that there is a great deal of information in common or that they are involved in the same relationships (who has parking permits, say). How do we handle these “same only different” cases in a pragmatic way?作者: 教育學(xué) 時間: 2025-3-24 00:25 作者: 擦試不掉 時間: 2025-3-24 03:26
t database design right the first time..Beginning Database Design, Second Edition. provides short, easy-to-read explanations of how to get database design right the first time. This book offers numerous examples to help you avoid the many pitfalls that entrap new and not-so-new database designers. T作者: defibrillator 時間: 2025-3-24 07:30 作者: 事先無準備 時間: 2025-3-24 12:13 作者: 高貴領(lǐng)導(dǎo) 時間: 2025-3-24 17:57
M. N. ?a?atay,N. G?rür,B. Alparbles. In this chapter, we take another look at some of these ideas and think about some alternative possibilities. In particular, we take a closer look at primary keys and how to choose them. We also take a look at how we can maintain referential integrity when data is being constantly updated.作者: Baffle 時間: 2025-3-24 22:28
https://doi.org/10.1007/978-94-010-0383-4estions we are asking, we will need to combine data from those tables in a number of different ways. This chapter is just a brief introduction to the art of querying. For further information you might be interested in looking at my book ..作者: 忍耐 時間: 2025-3-25 02:53 作者: 退潮 時間: 2025-3-25 04:20 作者: 樂章 時間: 2025-3-25 08:56
From Data Model to Relational Database Design,s and complexities of the real-world problem. We then looked at a number of situations that occur in many models in the hope that these would be useful when difficult situations arose in other contexts.作者: 延期 時間: 2025-3-25 12:10 作者: Parabola 時間: 2025-3-25 18:24 作者: CRUMB 時間: 2025-3-25 22:21
Other Implementations,base as a set of normalized tables with the relationships implemented by foreign keys. The previous two chapters showed how we could efficiently enter data into these tables and use queries to extract meaningful information and reports.作者: Frequency 時間: 2025-3-26 03:11 作者: Aqueous-Humor 時間: 2025-3-26 04:25 作者: Irrigate 時間: 2025-3-26 10:49
Earth and Environmental Sciences Library the system, and then figure out what data needs to be stored to support them. Use cases and class diagrams as shown in Figure 3-1 are a great way to start to consolidate our understanding of a problem.作者: FLACK 時間: 2025-3-26 16:40 作者: 商談 時間: 2025-3-26 17:02 作者: COM 時間: 2025-3-26 22:40
Lecture Notes in Computer Science not necessarily the most useful one. Often a table or spreadsheet is designed to mimic a possible data entry screen or a hoped—for report. This practice may be adequate for solving the immediate problem (e.g., storing the data somewhere); however, mimicking a data entry screen or report in your des作者: 入會 時間: 2025-3-27 03:22 作者: 鍍金 時間: 2025-3-27 08:32 作者: 親屬 時間: 2025-3-27 11:50 作者: 馬賽克 時間: 2025-3-27 16:59 作者: Corroborate 時間: 2025-3-27 19:17
https://doi.org/10.1007/978-3-031-60149-1eloped an initial data model. By looking carefully at the details of the model, we were able to develop questions to help understand further subtleties and complexities of the real-world problem. We then looked at a number of situations that occur in many models in the hope that these would be usefu作者: 態(tài)度暖昧 時間: 2025-3-27 23:49
M. N. ?a?atay,N. G?rür,B. Alpar relationships between classes with primary and foreign keys and then applied the ideas of normalization to ensure the attributes were in the right tables. In this chapter, we take another look at some of these ideas and think about some alternative possibilities. In particular, we take a closer loo作者: Absenteeism 時間: 2025-3-28 02:17
https://doi.org/10.1007/978-94-010-0383-4 this chapter, we are going to look at how to get information back out again. The data will be stored in many separate tables, and depending on the questions we are asking, we will need to combine data from those tables in a number of different ways. This chapter is just a brief introduction to the 作者: Wernickes-area 時間: 2025-3-28 07:58 作者: Cabinet 時間: 2025-3-28 14:00
Catastrophe Theory and Ecology, and the interrelation of the different data items. Chapters 7 through 9 showed how we could take the data model and represent it in a relational database as a set of normalized tables with the relationships implemented by foreign keys. The previous two chapters showed how we could efficiently enter作者: 鞏固 時間: 2025-3-28 17:55 作者: floaters 時間: 2025-3-28 19:40
Overview of TCLs in Smart Grids,We are doing pretty well at designing a database. So far, you have learned how use cases and a data model can help you understand many of the complexities of the problem you are trying to represent. In the previous chapter, you saw how to represent the main parts of the data model in a relational database. To recap:作者: grotto 時間: 2025-3-29 02:44 作者: 蠟燭 時間: 2025-3-29 05:02
Normalization,We are doing pretty well at designing a database. So far, you have learned how use cases and a data model can help you understand many of the complexities of the problem you are trying to represent. In the previous chapter, you saw how to represent the main parts of the data model in a relational database. To recap:作者: 愛國者 時間: 2025-3-29 09:29
Learning from the Data Model,first attempt at determining the data that are necessary to support those tasks and formed an initial data model, which we depicted with a class diagram. In this chapter, we look more closely at the data model to see how it can further our understanding of a database system.作者: APRON 時間: 2025-3-29 12:07
User Interface,. We specified these requirements in terms of use cases, and most fell into one of two categories: tasks a user would need to carry out to enter data efficiently and tasks for retrieving information in the form of different reports.作者: defenses 時間: 2025-3-29 16:38
Clare ChurcherBeginning Database Design, Second Edition helps you ask and answer important questions about your data so that you can avoid pitfalls and get database design right the first time.作者: 不足的東西 時間: 2025-3-29 21:07
http://image.papertrans.cn/b/image/182300.jpg作者: olfction 時間: 2025-3-30 01:30 作者: TOXIC 時間: 2025-3-30 07:57
M. N. ?a?atay,N. G?rür,B. Alpar. We specified these requirements in terms of use cases, and most fell into one of two categories: tasks a user would need to carry out to enter data efficiently and tasks for retrieving information in the form of different reports.作者: 清楚說話 時間: 2025-3-30 12:17 作者: ANTH 時間: 2025-3-30 14:42
