Understanding measures and dimensions

You will see the terms "measures" and "dimensions" throughout this book. Every data column that you import from a source to build a model in SAP Analytics Cloud must be marked either as a measure or a dimension. Measures are the columns by which an organization gauges its business operations and performance, while dimension columns contain the data used to qualify the measures.
These terms can be further expanded as follows:

• Measures: Measures are those fields that can be measured, aggregated, or used for mathematical operations. Measures are typically calculated data, such as dollar value or quantity sold, and they can be specified in terms of dimensions. For example, you might want to determine the sum of dollars for a given product in a given market over a given time period.
• Dimensions: A business uses measures to evaluate performance by well-established dimensions, for example, by time, product, and market. Dimensions are usually those fields that cannot be aggregated. Dimensions contain values that describe business entities (such as time, product, customer name, region, country, city, address, and so on). Within a given dimension, there may be many attributes. For example, the time dimension can contain the attributes year, quarter, month, week, and day. These attributes are used to drill into and across dimensions to get more detailed views of the data.

In relational database management systems (RDBMS) terminology, tables at the one end of a join are treated as dimension tables, and tables at the many end of a join as measure tables. The following figure illustrates the many-to-one joins to a table carrying measure data. In this diagram, all joins have the crow's feet symbol (indicating the many side) pointing into the measure table: