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Data Warehouse Design

Data Warehouse Design consists in collecting and filtering the user requirements. It involves the designer, end-users of DW and produces the specifications concerning. Data Warehouse Design includes Requirement Specification, Conceptual Design, Logical Design, Conclusions, Case study. | Data Warehouse Design by Duong Tuan Anh Faculty of Computer Science and Engineering, HCM City University of Technology. Sept. 2011 Outline Requirement Specification Conceptual Design Logical Design Conclusions Case study (M. Golfarelli, 1998) 1. Requirement Specification This phase consists in collecting and filtering the user requirements. It involves the designer, end-users of DW and produces the specifications concerning the choice of facts preliminary indications of the workload The choice of facts is based on the documentation of the operational information system. Facts are concepts of main interest for the decision making process, and correspond to events occurring in the enterprise world. If the operational information system is documented by ER schemes, a fact can be represented by an entity or an n-ary relationship. If it is documented by relational schemes, facts correspond to relation schemes. In general, entities or relationships representing frequently . | Data Warehouse Design by Duong Tuan Anh Faculty of Computer Science and Engineering, HCM City University of Technology. Sept. 2011 Outline Requirement Specification Conceptual Design Logical Design Conclusions Case study (M. Golfarelli, 1998) 1. Requirement Specification This phase consists in collecting and filtering the user requirements. It involves the designer, end-users of DW and produces the specifications concerning the choice of facts preliminary indications of the workload The choice of facts is based on the documentation of the operational information system. Facts are concepts of main interest for the decision making process, and correspond to events occurring in the enterprise world. If the operational information system is documented by ER schemes, a fact can be represented by an entity or an n-ary relationship. If it is documented by relational schemes, facts correspond to relation schemes. In general, entities or relationships representing frequently updated data are good candidates for defining facts. The preliminary workload is expressed in pseudo-natural language and is aimed at enabling the designer to identify dimensions and measures during conceptual design. For each fact, it should specify the most interesting measures and aggregations. 2. Conceptual Design of Data Warehouse The conceptual design of a DW produces a dimensional scheme, structured according to the Dimension Fact Model (DF model). A dimensional scheme consists of a set of fact schemes. The basic components of a fact schemes are fact, dimensions and hierarchies. A fact is a focus of interest for the enterprise; A dimension determines a point of view adopted for representing facts; A hierarchy determines how fact instances may be aggregated and selected significantly for the decision-making process. A fact scheme A fact scheme is structured as a tree whose root is a fact. The fact is represented by a box which reports the fact name and, typically, one or .