# Lookup
In this document, you’ll learn how to use the *Lookup* transformation in Astera Dataprep to enrich a dataset by bringing in additional fields from another source.
### Use Case
A university maintains a student's dataset, but roll numbers are stored separately. To prepare data for reporting and transcripts, the university needs to enrich the student's dataset with roll numbers, ensuring each student is matched correctly.
This lookup source may exist as a file, a shared project source or in a database table.
1. In the toolbar, click on *Lookup* and select the appropriate source type.
2. This will open the *Recipe Configuration – Lookup* panel. In this panel you can configure the source-specific settings (see tabs below).
{% tabs %}
{% tab title="File " %}
* **Browse Path**: Use this to manually browse and select your source file.
* **Path from Variable**: Use this when your file path is dynamic and parameterized. To learn more about using variables click [here](https://documentation.astera.com/variables#using-variables-in-recipes).
For this use case, we’ll use the *Browse Path* option.
{% endtab %}
{% tab title="Project Source" %}
* **Lookup Source:** Choose the source you want to use for your Lookup. All available sources will be visible in the drop-down.
{% endtab %}
{% tab title="Database Table" %}
* **Connection Name:** Select the shared connection you want to use. The drop-down lists all shared connections available in the project.
* **Table:** From the drop-down, choose the database table you want to lookup from with. In this example, we’ll select the *RollNo* table.
{% endtab %}
{% endtabs %}
* Provide a name for the lookup dataset (or keep the default name).
* **Keys:** Select the key fields to define how records will be matched. Astera will auto-detect matching fields, but you can modify them as needed.
* **Current Dataset Column**: Field from the current dataset.
* **Source Column**: Field from the lookup dataset.
* **Return Columns:** Choose which columns to return from the lookup source.
3. Once you’re done, click *Apply.* The result will appear in the grid with the new column(s) added.
*Apply.* The result will appear in the grid with the new column(s) added.
