This step provides the possibility to calculate the key for a variable value. The value must be of a complex type, i.e. of a type
that is specified in a .type file and not one of the built-in simple types such as Number.
At least one attribute in the type must be marked 'Part of Database Key'. Knowing the key of a value can be useful if it needs to be linked to another value (for instance as a secondary key in another table), or linked to data stored in a file.
Calculate Key can be configured using the following properties: