tailieunhanh - Building the Data Warehouse Third Edition phần 3

Hệ thống cổ điển Chu kỳ phát triển cuộc sống (SDLC) không làm việc trong thế giới của các nhà phân tích DSS. SDLC giả định Yêu cầu đó được biết đến khi bắt đầu thiết kế (hoặc ít nhất là con chó được phát hiện). Trong thế giới của các nhà phân tích DSS, tuy nhiên, yêu cầu mới là điều cuối cùng thường được phát hiện trong vòng đời phát triển DSS. | Uttama Reddy E64 CHAPTER 2 Data Warehouse The Standards Manual The data warehouse is relevant to many people-managers DSS analysts developers planners and so forth. In most organizations the data warehouse is new. Accordingly there should be an official organizational explanation and description of what is in the data warehouse and how the data warehouse can be used. Calling the explanation of what is inside the data warehouse a standards manual is probably deadly. Standards manuals have a dreary connotation and are famous for being ignored and gathering dust. Yet some form of internal publication is a necessary and worthwhile endeavor. The kinds of things the publication whatever it is called should contain are the following A description of what a data warehouse is A description of source systems feeding the warehouse How to use the data warehouse How to get help if there is a problem Who is responsible for what The migration plan for the warehouse How warehouse data relates to operational data How to use warehouse data for DSS When not to add data to the warehouse What kind of data is not in the warehouse A guide to the meta data that is available What the system of record is Auditing and the Data Warehouse An interesting issue that arises with data warehouses is whether auditing can be or should be done from them. Auditing can be done from the data warehouse. In the past there have been a few examples of detailed audits being performed there. But there are many reasons why auditing even if it can be done from the data warehouse should not be done from there. The primary reasons for not doing so are the following Data that otherwise would not find its way into the warehouse suddenly has to be there. Uttama Reddy The Data Warehouse Environment 65 The timing of data entry into the warehouse changes dramatically when auditing capability is required. The backup and recovery restrictions for the data warehouse change drastically when auditing capability is required.