Đang chuẩn bị liên kết để tải về tài liệu:
Building the Data Warehouse Third Edition phần 6

5-năm chân trời 1000000000 trong tràn và dữ liệu trên đĩa, đa số trong tràn, rất cẩn thận xem xét từ 100.000.000 Có thể một số granularity dữ liệu trong tràn, MOST dữ liệu trên đĩa, Một số Xem xét dữ liệu trên 10.000.000 granularity đĩa, 1.000.000 Hầu như bất kỳ thiết kế cơ sở dữ liệu cơ sở dữ liệu thiết kế và Cổ , tất cả các dữ liệu trên đĩa | Uttama Reddy The Data Warehouse and Technology 193 In this simple but common example where the contents of data stand naked over time the contents by themselves are quite inexplicable and unbelievable. When context is added to the contents of data over time the contents and the context become quite enlightening. To interpret and understand information over time a whole new dimension of context is required. While content of information remains important the comparison and understanding of information over time mandates that context be an equal partner to content. And in years past context has been an undiscovered unexplored dimension of information. Three Types of Contextual Information Three levels of contextual information must be managed Simple contextual information Complex contextual information External contextual information Simple contextual information relates to the basic structure of data itself and includes such things as these The structure of data The encoding of data The naming conventions used for data The metrics describing the data such as How much data there is How fast the data is growing What sectors of the data are growing How the data is being used Simple contextual information has been managed in the past by dictionaries directories system monitors and so forth. Complex contextual information describes the same data as simple contextual information but from a different perspective. This type of information addresses such aspects of data as these Product definitions Marketing territories Pricing Packaging Organization structure Distribution Uttama Reddy 194 CHAPTER 5 Complex contextual information is some of the most useful and at the same time some of the most elusive information there is to capture. It is elusive because it is taken for granted and is in the background. It is so basic that no one thinks to define what it is or how it changes over time. And yet in the long run complex contextual information plays an extremely important role .