Set Variables

This transform accepts one (and only one) row of data to set the value of a variable. It is important to isolate a single row for this transform, a simple way to do this is using the Blocking transform

Variables have no type in Hop (casted as strings). If working with formulas for example, it may not have a type so be sure to convert to string if necessary (can use the TEXT function).

Variables set with Set Variable are not available to use in the current pipeline. If set values are needed in the current pipeline the values will have to come from fields.

Note that variables cannot be passed upstream between pipelines. Parameters are best passed downstream to avoid threading issues. A nested pipeline is technically the same pipeline, so variables are inherited in the initialization phase.

Though you cannot pass parameters and variables upstream (in nested or sequential pipelines) you can pass data rows back up a pipeline via the following pattern in the samples project: samples/loops/pipeline-executor.hpl

A variable can be set in one pipeline and be available in the next pipeline (named pipeline) that is in the loop of a pipeline executor. If you are using a pipeline executor child, the parent pipeline does not restart and does not get any set variables. The new variable name to set in a child pipeline is shown below in the second column.