Control / params · All operations

Read variables into a table

A variant of Set parameters

Turn the current variables or parameters into rows or columns of a table.

Status

In arcform

Not built yet

arcform does not do this yet; it would live in how a Protocol runs. Its place on the roadmap

What other tools call it

Meridian's classification; an independent blind rating agreed on 95.7% of 324 rows (variant, version 3).

Apache Hop (1)
  • Get variablesread 2026-09-27

    Put variable values into fields of new or existing rows

DuckDB (1)
  • duckdb_variablesread 2026-09-27

    duckdb_variables table function

EasyMorph (1)
  • Parameter tableread 2026-09-27

    Emit one row with each project parameter's value as a column

KNIME Analytics Platform (2)
Pentaho Data Integration (2)
  • Get Session Variablesread 2026-09-27

    Read the value of a Pentaho Server session variable

  • Get Variablesread 2026-09-27

    Put the values of environment or Kettle variables into fields

Talend (1)
  • tContextDumpread 2026-09-27

    Emit the context variables of the current Job as rows, for a file, a table or tContextLoad

Background

EasyMorph's Parameter table action creates a single-row dataset in which each column displays one project parameter's name and value.[1] In DuckDB, the duckdb_variables() function returns metadata about the variables available in the instance: each variable's name, value and type.[2] Apache Hop's Get variables transform creates fields from variable values, and is needed only when a variable's value is wanted in a field.[3]

When to use it

EasyMorph's Parameter table is a convenient way to start processing input values passed into a project by another project during iterations.[1] EasyMorph's Parameter table is not updated automatically when parameters are modified in the Parameter Editor, and has to be rerun to pick up the changes.[1] In Apache Hop, workflow and environment variables are set only once, a pipeline needs to start to get new variables, and a running pipeline cannot fetch new variable values.[3]

The method

In Apache Hop, the Get variables transform can be a pipeline's source, starting without any input, and still reads incoming rows when there are some.[3] Apache Hop's Get variables transform needs a data type for each field, such as String, Date, Number, Boolean or Int, and gives errors without one.[3] In Apache Hop's Get variables transform, a field can combine a variable with text, so ${java.io.tmpdir}/hop/tempfile.txt expands to /tmp/hop/tempfile.txt on Unix-like systems.[3]

KNIME's Variable to Table Row node extracts flow variables and puts them into a single-row table.[4] KNIME's Variable to Table Column node extracts the variables carried along the flow and appends them to an input table.[5]

Sources

  1. [1]PARAMETER TABLE [EasyMorph Help]documentation
  2. [2]DuckDB_% Metadata Functions – DuckDBdocumentation
  3. [3]Get variables | Apache Hopdocumentation
  4. [4]Variable to Table Rowdocumentation
  5. [5]Variable to Table Columndocumentation