One important activity when you create calculation views, is to express the relationships between the different data sources used by a model. Most often, this is done by using joins, a classical artifact in any relational database management system (RDBMS).
A specific node type, the Join node, is used in modeling to materialize joins between one or more data sources (tables, calculation views, and so on).
In addition, the Star Join node, which is used to model a star schema, also defines one or several joins between a main data sources (fact "table") and DIMENSION calculation views.
For each Join node, you must define which columns of the two joined sources must participate in the join, as well as the join type, as discussed in the lesson Connecting Tables. You can also specify the cardinality, with the help of the Propose Cardinality feature, but only if you are sure that the cardinality you provide corresponds to how the data is actually organized.
Sample Business Case and Data
To illustrate the behavior of the different types of joins in SAP HANA Cloud, consider the following tables:
Sales Order
Customer
State
The objective is to join these tables to retrieve the sales order amounts (facts) with the customer information, including the states in which the customers reside.

To begin with, you can make the following observations:
Sales Order 8 does not have a customer master record.
Customer TOM does not have any orders.
State TX does not have a description.
No customer resides in Alabama.
Join Type Summary

There are different types of joins. The inner and outer joins are similar to other database management systems. Others are specific to SAP HANA Cloud and address specific requirements such as optimization (for example, the Referential Join), ease of use with typical SAP Business Suite data model (for example, the Text join), and others. As an aside, some of the join types listed in the table consist of a specific option or configuration. For example, the Temporal Join is an Inner Join to which you add time-related conditions.
You can review the typical use cases for the different join types.
This table builds on a scenario similar to the one just described (Sample Data for Business Example), assuming that a fact table (considered as the left table) is joined to a dimension table (considered as the right table).
Each join type will now be presented in detail.