# Mapping columns

Mapping columns are a useful feature for performing ad-hoc data enrichment by manually associating values from a dimension with custom mapped values.

## 1. Creating mapping columns

Mapping columns can be created from the Enrich Data section > **Manual Input**.

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They let you input manual mappings for the values of your dimension columns.

For example, you can manually define the desks at which your traders work:

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*Here, we are defining a mapping column for the Trader dimension. A Desk name was manually selected for each trader of the firm.*

> When a dimension has a high cardinality, some of the available values might be missing from the displayed list. It is recommended to use CSV files to configure exhaustive mappings of large dimensions.

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The name of the newly created mapping column should be entered in the header of the input column, as shown on the screenshot above.

**CSV imports and exports:** Your mapping can be exported as a CSV file and imported into the software.

Below, the CSV associated with the trading desk mapping:

```csv
trader,desk
Alice Brown,EXO
Bob Johnson,EXO
Jane Smith,EXO
John Doe,EXO
Joojoo Boy,CRYPTO
Tom Davis,CRYPTO
```

This CSV file can be edited manually and loaded back in KAWA.

**Handling values without mapping:**

When the mapping does not cover all the values of your dimension, for example: after an ETL, a new trader was added into the system - and they were not assigned to a desk yet.

* *Empty cell:* All the unmapped values will not be filled and left empty.
* *Original value:* Unmapped values will stay unchanged. A trader without a desk will be rendered as the trader name without change.
* *Custom value:* You can define a placeholder there for unmapped values like: N/A etc...

## 2. Editing a mapping column

In the 3 dots menu of a mapping column, click on **Edit Mapping**. You can then change the mapped values (either manually or by loading a new CSV file), you can rename the column and change the behavior for unmapped values.