# Lookup Fields tab

![Avro Input Lookup Fields Tab](https://3411831820-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FAYwCj9fPr1B2pjC11IOQ%2Fuploads%2Fgit-blob-171d2e2e7f53fe47600bc4e8c70718fdc5e096a7%2FPDI_TransStep_Avro_Input_Lookup_Fields_Tab.png?alt=media)

You can use the **Lookup Fields** tab to create variables and map them to a specific field to use as lookups into an Avro structure at decoding time. The table in this tab defines the following field properties:

| Field Property    | Description                                                    |
| ----------------- | -------------------------------------------------------------- |
| **Name**          | The name of the incoming field                                 |
| **Variable**      | The variable you want to use as the value of an incoming field |
| **Default value** | The value to use when the incoming field value is null         |

Click **Get fields** to populate the **Name** column with names of the incoming fields.