Star Schema

A typical star schema includes a dimension table around the fact table on a large fact table and a set of logic. 
　　fact table is the core of the star schema, the fact table by the primary key and metrics of two parts. Each star schema dimension table primary key combination of the primary key of the fact table. Large amounts of data stored in the fact table, is closely related to the same topic, metric data users are most concerned about. Star hotels most concern is customer consumption. As requirements analysis, the basis of the facts described in the table need is the fact that the guests consume the lowest granularity. Even someone guests what promotional tools were what form of consumption at a time, how much the amount of consumption capacity. Therefore, in the fact table, to accurately record each guest consumption patterns, consumer prices, promotions, promotional discounts, the amount of consumption, costs, profits and other metrics. 
　　dimension is observable facts, analyze the theme of the angle. Set of dimension tables is the key to building a data warehouse data model. Dimension table primary key is connected with the fact table. Users rely dimension attribute dimension table, to obtain data to support decision-making from the fact table. Operating around the theme, hotel management data mart has the following typical dimensions and attributes: 
　　customer dimension: In the customer dimension, the need to establish basic information about customers. Analysis for decision-making needs, and clients into permanent clients and mobile clients. 
　　consumer items dimensions: business-star hotel, guests want to provide high-quality consumer, a variety of consumer items. The regular consumer items summarized as: rooms, catering, entertainment and other four categories. Each class has its consumer consumption detail description of the content. 
　　time dimension: the multidimensional data structure of the data warehouse, the time dimension is a dimension often essential. Because every "sell the fact" is in a certain period of time or occur. When using dimension for demand, time, day, month, year four properties. 
　　promotional dimension: competition in the industry, the hotels have adopted all kinds of promotions. Promotional increased turnover, but also increases the operating costs. Form and effect of promotion of great value to the decision-making of managers. In the promotional dimension describes some typical promotions: discounts, intermediaries, joint venture and other property as a dimension. 