Exporting Structure and DataThe options in Structure section are: Add custom comment into header: We can add our own comments for this export (for example, 'Monthly backup') which will show in the export headers (after the PHP version number). If the comment has more than one line, we must use the special character \n to separate each line. Enclose export in a transaction: St...
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Comparison of Data Warehouse MethodologiesFor the MD approach, the multidimensional or star schema data model is easy to understand by the business community. The data model is generally less complex and resembles the way many business community members think about their data—that is, they think in terms of multiple dimensions, for example, “Give me all the sales revenues for each store, i...
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Maintaining the Modelscorrespond to each subject area. (This technique cannot be used if the tool does not provide the ability to divide the model into subject area views.) This technique facilitates the grouping of the data entities by subject area and the provision of views accordingly. The major advantages of this technique are: ■■ Each entity is assigned to a subjec...
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Data warehouse optimizationPerformed by the database’s optimizer, and as a result it would either look at all rows for the specific date and scan for customer or look at all rows for the customer and scan for date. If, on the other hand, you defined a compound b-tree index using date and customer, it would use that index to locate the rows directly. The compound index would ...
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Modeling transactionsDelta Snapshot Interface The delta snapshot is a commonly used interface for reference data, such as a customer master list. The basic delta snapshot would contain a row or transaction that changed since the last extraction. It would contain the current state of all attributes without information about what, in particular, had changed. This is the ...
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Modeling hierarchiesThe lowest level of the customer’s distribution hierarchy is the ship-tocustomer location. These are grouped under sold-to customers, which represent the customer’s purchasing representatives. These are further grouped into planning customers, which is the lowest level at which sales plans are estimated. Figure 7.9 shows the full hierarchy. Capacit...
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Modeling the Calendarmaintain calendars on these terms, allowing the user to see April 18, 2002 instead of day 198, and yet internally, such systems continue to count days based on working and nonworking days. By their very nature, factory calendars are localized. That is, each production facility may have its own factory calendar to reflect the workdays and shifts wit...
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Developing the ModelStep 3: Add Derived Data The third step in developing the data warehouse model is to add derived data. Derived data is data that results from performing a mathematical operation on one or more other data elements. Derived data is incorporated into the data warehouse model for two major reasons—to ensure consistency, and to improve data delivery per...
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Understanding the Business ModelIntroductions. The participants introduce themselves, and the session objectives are reviewed. Education. Education is provided on the relevant concepts, on the process, and on the starter model. Review and refinement of subject areas. The subject areas in the starter model are reviewed, and a set of subject areas is derived. Definitions for those ...
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Fundamental Relational ConceptsEvery data-modeling technique has its own set of terms, definitions, and techniques. This vernacular permits us to understand complex and difficult concepts and to use them to design complex databases. This book applies relational data-modeling techniques for developing the data warehouse data model. To that end, this chapter introduces the terms a...
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