自上而下与自下而上 - 标准化
有人可以为我描述一下数据库(即关系数据库)自上而下规范化和自下而上规范化之间的区别吗?
Could someone describe for me the differences between top down normalisation and bottom up normalisation with regards to databases, namely relational databases.
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我希望您指的是自上而下的设计与自下而上的设计 - 规范化只是您用来完成数据库设计的方法和原则的一个方面。
自上而下意味着您从一组要求开始。通常,您首先要确定需要表示数据的事物类型,然后确定这些事物的属性,这些属性将成为表中的属性。
自下而上的设计意味着您将获得某种数据结构作为开始,例如您需要合并到设计中的属性或表和属性的列表。通常,当您拥有现有数据库或数据源时,可能会发生这种情况,这在商业智能或数据集成项目中很常见。
I expect you mean top-down design vs bottom-up design - normalization being just one aspect of the methods and principles you would use to complete a database design.
Top-down means you start with a set of requirements. Usually you begin by identifying the types of things that you need to represent data about and then identify the attributes of those things, which will become attributes in tables.
Bottom-up design means you are given some kind of data structures to start with, e.g. a list of attributes or tables and attributes which you need to incorporate into a design. Typically this might happen where you have an existing database or data source, as is common in business intelligence or data integration projects.