相反放置
发表于 2025-3-25 03:40:43
Developing a Data Model,ry out. Tasks were represented with use cases, and a simple data model was developed to represent the required data. In Chapter 4, you saw that a great deal can be learned about a problem by questioning some of the details of simple relationships, particularly the number of objects involved at each
NICHE
发表于 2025-3-25 11:07:29
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
stroke
发表于 2025-3-25 14:34:29
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enterprise
发表于 2025-3-25 17:54:38
More on Keys and Constraints, 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
vibrant
发表于 2025-3-25 22:38:09
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CAND
发表于 2025-3-26 03:12:29
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
向下五度才偏
发表于 2025-3-26 05:31:52
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清澈
发表于 2025-3-26 10:36:26
Karittha Im-orb,Amornchai ArpornwichanopThe decision to set up a small database usually arises because there is some specific task in mind: a scientist may have some experimental results that need safekeeping; a small business may wish to produce invoices and monthly statements for its customers; a sports club may want to keep track of teams and subscriptions
monochromatic
发表于 2025-3-26 13:12:46
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JAUNT
发表于 2025-3-26 17:56:03
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