> For the complete documentation index, see [llms.txt](https://docs.collibra.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.collibra.com/data-quality-self-hosted/core-concepts/explorer/create-a-dq-job/transform.md). # Transform {% hint style="warning" %} Transform is only available in Pullup mode. If you are using Pushdown mode, proceed to the next available step. {% endhint %} Transform allows you to override existing columns or create new ones based on the data in existing ones by performing the following operations: * Convert a column to a date, string, integer, double, or long data type. * Concatenate 2 or 3 string columns. * Replace empty spaces in specified columns with NULL. * Perform window functions on groups of rows. * Add custom transform expressions. {% hint style="info" %} Transform is disabled by default. {% endhint %} ## Steps {% stepper %} {% step %} On the stepper, click **Transform**.\ :chevrons-right: The Transform step opens. {% endstep %} {% step %} Select from the following options, as needed.
OptionDescription
Add Collibra DQ Date Column

Adds a synthetic run date column.

This can be helpful when your file does not contain dates that are easy to handle.

Flatten

Refers to the level of nesting in your file.

Data Quality & Observability (self-hosted) traverses all levels, which can result in highly nested data being expanded into many rows per nested object. This can significantly impact processing performance, so use this feature with caution.

Multi-line

Refers to the content of the file being more than one line.

There are limitations in Explorer for remote file systems, file uploads, and temporary files. The user interface doesn't support multi-line input for these file types, but you can manually supply them using using the command line.

Zero Fill NullReplaces NULL values with 0.
Replace all field values of [value] with NULLReplaces all values of the column you specify with NULL.
{% endstep %} {% step %} To the right of the Transform screen, click **+ Add**.\ :chevrons-right: The Add a Transform modal appears. {% endstep %} {% step %} Select one of the following options and follow the steps accordingly. {% tabs %} {% tab title="Override a Column" %} {% stepper %} {% step %} Click the **Override a Column** option. {% endstep %} {% step %} Click the **Operation** dropdown menu and select an option.
OperationDescription
to DateConverts a string column to a date type column.
to StringConverts a column to a string type column.
to IntConverts a column to an integer type column.
to DoubleConverts a column to a double type column.
to LongConverts a column to a long type column.
Concat(X, Y)Concatenates two string type columns, where "X" represents the first column and "Y" the second. Select the columns from the Column dropdown menus to the right of the Operation dropdown menu.
Concat(X, Y, Z)

Concatenates three string type columns where "X" represents the first column, "Y" the second, and "Z" the third.

Select the columns from the Column dropdown menus to the right of the Operation dropdown menu.

ReplaceReplaces empty spaces in a specified column with NULL.
Window Functions

Performs window functions on groups of rows.

This option requires additional selections outlined in the following steps.

  1. Select an option from the Function dropdown menu.
  2. Select a column from the Column dropdown menu.
  3. Optionally select the Group by checkbox, then select the column(s) to group the window function.
  4. Optionally select the Order by checkbox, then select the column(s) in the order you want them to appear.
CustomAdds custom transform expressions. Manually update the Expression input field after selecting a column from the Column dropdown.
{% endstep %} {% step %} Click the **Column** dropdown and select an option. {% hint style="success" %} If you already selected the columns after choosing Window Functions or one of the Concat options, you can skip this step. {% endhint %} {% endstep %} {% step %} Review or manually edit the **Expression** input field, as needed. {% endstep %} {% endstepper %} {% endtab %} {% tab title="Create a new Column" %} {% stepper %} {% step %} Click the **Create a new Column** option. {% endstep %} {% step %} Enter a column name for your new column in the input field to the right of the Create a new Column option. {% endstep %} {% step %} Click the **Operation** dropdown menu and select an option.
OperationDescription
to DateConverts a string column to a date type column.
to StringConverts a column to a string type column.
to IntConverts a column to an integer type column.
to DoubleConverts a column to a double type column.
to LongConverts a column to a long type column.
Concat(X, Y)Concatenates two string type columns, where "X" represents the first column and "Y" the second. Select the columns from the Column dropdown menus to the right of the Operation dropdown menu.
Concat(X, Y, Z)

Concatenates three string type columns where "X" represents the first column, "Y" the second, and "Z" the third.

Select the columns from the Column dropdown menus to the right of the Operation dropdown menu.

ReplaceReplaces empty spaces in a specified column with NULL.
Window Functions

Performs window functions on groups of rows.

This option requires additional selections outlined in the following steps.

  1. Select an option from the Function dropdown menu.
  2. Select a column from the Column dropdown menu.
  3. Optionally select the Group by checkbox, then select the column(s) to group the window function.
  4. Optionally select the Order by checkbox, then select the column(s) in the order you want them to appear.
CustomAdds custom transform expressions. Manually update the Expression input field after selecting a column from the Column dropdown.
{% endstep %} {% step %} Click the **Column** dropdown and select an option. {% hint style="success" %} If you already selected the columns after choosing Window Functions or one of the Concat options, you can skip this step. {% endhint %} {% endstep %} {% step %} Review or manually edit the **Expression** input field, as needed. {% endstep %} {% endstepper %} {% endtab %} {% endtabs %} {% endstep %} {% step %} Click **Save**. {% endstep %} {% step %} Optionally repeat steps 3-5 to add additional transforms. {% endstep %} {% step %} Continue to the next step on the stepper or click the right arrow on the right side of the page. {% endstep %} {% endstepper %}