Building the Data Warehouse

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The creation of a data warehouse record is triggered by an activity or an event that has occurred in the operational environment. In some cases, an event— such as a sale—has occurred. In other cases, the regular passage of time has occurred, such as the end of the month or the end of the week.


A profile record is a composite record made up of many different historical activities. The profile record is a composite representation of data.


The star join is a database design technique that is sometimes mistakenly applied to the data warehouse environment. The star join multidimensional approach is an approach where database design is based on the occurrences of data within a subject area and how that data will be accessed. Star join design applies to the world of data marts, not the world of data warehouses. It is a mistake to build a data warehouse with a star join because the data warehouse will end up being optimal for one set of users at the expense of everyone else.

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The single most important design issue facing the data warehouse developer is determining the granularity. When the granularity is properly set, the remaining aspects of design and implementation flow smoothly; when it is not properly set, every other aspect is awkward.


Granularity is also important to the warehouse architect because it affects all of the environments that depend on the warehouse for data. Granularity affects how efficiently data can be shipped to the different environments determines the types of analysis that can be done.

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