Parameter (Constants)

[AngelaO]

Question

How do I pass a parameter/constant in a workflow?

Answer

You can use a workflow constant to pass a parameter. Click on the Workflow - Configuration - Workflow tab. Click the + button to add a new User type constant, and give your constant a name and value!

It is quite common to hardcode values (‘constants’) in workflows using any of the following ways:

1. Text input tool
2. Variables within formula tool
3. Hardcode the values within formula/any other transformation tools

If the values are hardcoded within tools, especially in very large or complex workflows, maintenance can be difficult. The ‘constants’ property allows us to define all static variables in one place, so that they are accessible throughout the entire workflow.

[bluebrent]

what is the syntax used to create a string that includes a user defined constant? Lets say for instance I have a user defined constant PYYY = 2017, but I want to use a filter, formula, or even input tool that has a variation of this constant in it. i.e. 201701 or DataTable2017. I am trying to keep the number of constants to a minimum so rather than creating a anew variable for each variation, I would like to be able to make adjustments to my constants on the fly. Does the syntax differ depending on tool? or based on the datatype of the user defined constant? Thank you very much in advance.

[bluebrent]

I am also wondering if it would be possible to have constants depend upon each other, or have constants be created in the workflow. Currently, I have a workflow that has many date constants. When the file gets ran, all of these constants need to be updated. I am hoping to find a way that I can update only 1 constant, and then have the rest of the dates automatically adjust to this new date. Is this possible, and if so, how might I accomplish this? I realize I can have every tool reference this 1 date and adjust it accordingly, but this does not seem like the best solution possible. Please and thank you for the help!