Dimensions of the data model
A dimension represents a single set of objects or
events in the real world. Each dimension that you identify for the
data model gets implemented as a dimension table. Dimensions are the
qualifiers that make the measures of the fact table meaningful, because
they answer the what, when, and where aspects of a question. For example,
consider the following business questions, for which the dimensions
are italicized:
- What accounts produced the highest revenue last year?
- What was our profit by vendor?
- How many units were sold for each product?
In the preceding set of questions, revenue, profit, and units sold are measures (not dimensions), as each represents quantitative or factual data.