Before introducing calculation views in SAP HANA Cloud, you should become familiar with some key modeling concepts and the terms that are frequently used.
Measure and Attribute
A data model usually contains a selection of measures and attributes.
Measure Versus Attribute
| Measure | Attribute | |
|---|---|---|
| What is it? | A numeric value, such as a price or quantity, on which you can process arithmetic or statistics operations, such as sum, average, top N values, and calculations. | A descriptive element such as 'country' that is used the provide context for a measure. For example 'Sales Revenue by France'. |
| Examples |
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Attributes are used to filter or aggregate the measures, in order to answer questions such as the following:
What are the total sales originating from Hamburg?
What is the sales revenue for Cars in 2022?
Dimension
A dimension is a group of related attributes. In the example below, we see a dimension called Product. This dimension includes various related attributes including product name, category, supplier.
Dimensions are re-useable objects. When they have been created, they can are shared by developers and used to develop star schemas.
Star Schema
A star schema is a very powerful type of data model that we can create in SAP HANA Cloud. A star schema invokes a powerful OLAP engine to provide fast slice-and-dice across data.
Watch this video to learn about the Star Schema.
Note
A fact table can be one table but it is often defined from a combination of tables to produce a view of a transaction, such as a sales order. Dimensions are then connected to the fact table to provide additional, descriptive information about the transaction, such as, the country of the customer.Hierarchy
A hierarchy is a structured representation of an organization, a list of products, the time dimension, and so on, using levels.
It is often used to provide the easy navigation of a large data set in a drill-down. You can define one or more hierarchies in calculation views that provide the end user with a convenient and natural way to navigate their data.
Watch this video to learn about the hierarchy concept.
Semantics
The term semantics is used to describe the meaning of an attribute or a measure, for example:
A monetary value
For example, the total amount sold would need to indicate the currency (for example USD, EUR, or GBP). An amount without a currency is meaningless.
A quantity, weight, volume, or distance
For example, quantity would need to specify the unit of measurement in which the data is expressed. Again, a quantity without a unit of measurement is meaningless.
In SAP HANA Cloud, we can add semantics to measures, attributes, or an entire calculation view. Semantic information is essential in the final report to provide the business user with important information about the data. This information is often not available in the original source tables but can easily be added by the developer in the calculation view.
