# Fields

You can specify what fields to update and insert in your Salesforce database through the **Fields** table. Click **Get fields** to populate the table with input from the PDI data stream.

The table contains the following columns:

| Column               | Description                                                                                                                                                                                                                                                                                                      |
| -------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Module field**     | The name of the field within the **Module**.                                                                                                                                                                                                                                                                     |
| **Stream field**     | The name of the field in the PDI data stream.                                                                                                                                                                                                                                                                    |
| **Use External id?** | <p>The flag indicating whether the field links to an external ID. Select <strong>Y</strong> (Yes) or <strong>N</strong> (No).</p><p>To resolve the ID, Salesforce needs the object type, column name, and relationship name in the following syntax:</p><p><code>Object name.column name/relationship</code></p> |

Optionally, click \*\*Edit mapping\*\* to specify custom mapping. For example, you can map a single PDI field to multiple Salesforce fields.