# tWriteDynamicFields Creates a dynamic schema from input columns in the component. tWriteDynamicFields creates an output dynamic column from input columns. ## tWriteDynamicFields Standard properties These properties are used to configure tWriteDynamicFields running in the Standard Job framework. The Standard tWriteDynamicFields component belongs to the Processing family. The component in this framework is available in all subscription-based Talend products. ## Basic settings | Properties | Description | | --- | --- | | Schema and
Edit Schema |

A schema is a row description, it defines the number of fields to be processed and passed on to the next component. The schema is either Built-in or stored remotely in the Repository.

Click Edit schema to make changes to the schema. If the current schema is of the Repository type, three options are available:
- View schema: choose this option to view the schema only.
- Change to built-in property: choose this option to change the schema to Built-in for local changes.
- Update repository connection: choose this option to change the schema stored in the repository and decide whether to propagate the changes to all the Jobs upon completion.
  
  If you just want to propagate the changes to the current Job, you can select No upon completion and choose this schema metadata again in the Repository Content window.
Click Sync columns to retrieve the schema from the previous component in the Job.
Built-in: You create the schema and store it locally for the relevant component. For more information about a component schema in its Basic settings tab, see Basic settings tab.
Repository: You have already created the schema and stored it in the Repository. You can reuse it in various projects and Job flowcharts. For more information about a component schema in its Basic settings tab, see Basic settings tab.

| ## Advanced settings | Properties | Description | | --- | --- | | tStatCatcher
Statistics | Select this check box to gather the Job
processing metadata at a Job level as well as at
each component level. | ## Global Variables | Variables | Description | | --- | --- | | Global Variables | ERROR\_MESSAGE: the error message generated by the
component when an error occurs. This is an After variable and it returns a string. This
variable functions only if the Die on error checkbox is
cleared, if the component has this checkbox.

NB\_LINE: the number
of rows read by an input component or transferred to an output component. This is an
After variable and it returns an integer.

A Flow variable functions during the execution of a component
while an After variable functions after the execution of the component.

To fill up a field or expression with a variable, press Ctrl+Space to access the variable list and choose the variable to use from
it.

For more information about variables, see [Using contexts and variables](https://help.qlik.com/talend/r/en-US/8.0/studio-user-guide/contexts-and-variables). | ## Usage | Usage guidance | Description | | --- | --- | | **Usage rule** | This component handles flow of data
therefore it requires input and output
components. | **Related concepts** * [Creating a dynamic column and extract its content](https://help.qlik.com/talend/en-US/components/8.0/processing/twritedynamicfields-textractdynamicfields-tlogrow-trowgenerator-creating-dynamic-column-and-extract-its-content-standard-component-enterprise-this) * [Extracting the contents of a dynamic column via tJavaRow](https://help.qlik.com/talend/en-US/components/8.0/processing/twritedynamicfields-tfixedflowinput-tjavarow-tlogrow-extracting-contents-of-dynamic-column-via-tjavarow-standard-component-enterprise-in-this)