Concepts → Expression
An expression returns a scalar or an array of values of a specific data type. An expression can consist of built-in functions, built-in system variables, and other referenceable objects valid for the expression context.
You can create complex expressions with the Formula Builder using any of the following as allowed by the expression context:
- Built-in function
- Built-in system variable
- Built-in system date variable
- Business schema view column
- Business schema view formula column
- External session variable
- Global variable
- Incorta Analyzer Table column
- ncorta Analyzer Table formula column
- Incorta View column
- Incorta View formula column
- Internal session variable
- Presentation variable
- Physical schema table column
- Physical schema table formula column
The expression context determines the validation rules for the expression itself and the limitations of the expression.
For example, the expression context of a physical schema table formula column allows only for referenceable objects within the scope of physical schemas and the Loader Service. For this reason, when creating a formula column in the Table Editor, it is not possible to reference a business schema view column in the formula column expression as a business schema view column is a runtime reference to an in-memory object in the Analytics Service.
An example of a contextual limitation is a Load Filter expression. A filter expression for a load filter can only reference a filterable column that exists in the entity itself.
In order to reference a column or variable in an expression, you must have View access rights to the grandparent object (physical schema or business schema).
A global variable is available to all users. It is not possible to assign access rights to a global variable.
There are several types of expressions that you can create using the Formula Builder:
- A formula expression for a formula column in a physical schema table, Incorta Analyzer Table, business schema view, Incorta View, or insight
- An internal query expression for an internal session variable
- A filter expression for a filter expression session variable, dashboards filter, insight filter, physical schema table runtime security filter, or physical schema table load filter.