Nó là hợp pháp. Đây là Đơn giản chỉ cần nghĩ làm thế nào DSS Các nhà phân tích và ứng xử như thế nào Họ kinh doanh của họ. Nó là phổ biến. Các nhà phân tích xung quanh thế giới DSS nghĩ như thế này. Nó đã tác động sâu sắc trên một con đường là kho dữ liệu về cách phát triển và hệ thống kho dữ liệu đang sử dụng nhà phát triển. | Uttama Reddy Evolution of Decision Support Systems 21 The attitude of the DSS analyst is important for the following reasons It is legitimate. This is simply how DSS analysts think and how they conduct their business. It is pervasive. DSS analysts around the world think like this. It has a profound effect on the way the data warehouse is developed and on how systems using the data warehouse are developed. The classical system development life cycle SDLC does not work in the world of the DSS analyst. The SDLC assumes that requirements are known at the start of design or at least can be discovered . In the world of the DSS analyst though new requirements usually are the last thing to be discovered in the DSS development life cycle. The DSS analyst starts with existing requirements but factoring in new requirements is almost an impossibility. A very different development life cycle is associated with the data warehouse. The Development Life Cycle We have seen how operational data is usually application oriented and as a consequence is unintegrated whereas data warehouse data must be integrated. Other major differences also exist between the operational level of data and processing and the data warehouse level of data and processing. The underlying development life cycles of these systems can be a profound concern as shown in Figure . Figure shows that the operational environment is supported by the classical systems development life cycle the SDLC . The SDLC is often called the waterfall development approach because the different activities are specified and one activity-upon its completion-spills down into the next activity and triggers its start. The development of the data warehouse operates under a very different life cycle sometimes called the CLDS the reverse of the SDLC . The classical SDLC is driven by requirements. In order to build systems you must first understand the requirements. Then you go into stages of design and development. The CLDS is .
