> ## Documentation Index
> Fetch the complete documentation index at: https://docs.abbyy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Using data catalogs

> Use data catalogs to validate and auto-populate extracted data from a Document skill — including ERP data, currency lists, and custom lookups.

Data catalogs contain information that facilitates document recognition. This information can include data from a customer's ERP system (for example, vendor and purchase order data) or any other relevant data, such as information about the currency used, a list of airports for a specific country, or a list of an organization's holidays. You can use data catalogs in your Document skills to:

* Improve the accuracy of data extraction.
* Verify extracted data.
* Allow the user to select a record from the dropdown during manual review to automatically populate the other fields with the data from the selected record.

A data catalog is a table of data — you must populate it before it can be used.

To match document fields against catalog records, set up [data catalog lookup rules](/vantage/documentation/skill-designer/document/rule-verification/setting-lookup-rules). When Vantage processes a document, it searches for the catalog record that has the most field values matching the document. If a match is found, Vantage populates the matching document fields from that record. If no record matches, or if multiple records match, the rule generates an error and the operator can pick a record manually during review.

<Note>
  A data catalog can hold up to **500,000 records**. Each field value can be up to **256 characters** long.
</Note>

In ABBYY Vantage, data catalogs are created for built-in Document skills. For example:

* For an Invoice skill, data catalogs named **Vendors**, **BusinessUnits**, **PurchaseOrders**, and **PurchaseOrderItems** are created.
* For a Purchase Order skill, data catalogs named **Buyers** and **Suppliers** are created.

<Warning>
  Predefined data catalogs have a fixed structure and normalization types that must not be modified.
</Warning>

To open the list of data catalogs, click **Data Catalogs** in the menu on the left.

<Note>
  **Role requirement:** Creating and updating data catalogs depends on the user's role. See [Role-based access control](/vantage/documentation/tenant-admin/tenant-management/role-based-access).
</Note>

## Create data catalogs

You can create a data catalog when editing or importing a Document skill derived from a built-in. Built-in skills can't be edited directly — duplicate the skill first, and Vantage creates the data catalog automatically.

You can create a data catalog in one of two ways:

* From a CSV file.
* By entering columns manually.

For more information, see [Creating data catalogs](/vantage/documentation/skill-designer/document/using-data-catalogs/create).

## Update data catalogs

You can add data to a data catalog in the following ways:

* Upload a CSV file via the UI.
* Upload a CSV file via shared folders.
* Use the Vantage API for data in JSON format.

<Note>
  Updated data catalogs are available to all skills in the tenant, but only for **documents uploaded after the update**. For documents uploaded before the update, the pre-update data is used.
</Note>

## Related topics

<CardGroup cols={3}>
  <Card title="Create data catalogs" icon="plus" href="/vantage/documentation/skill-designer/document/using-data-catalogs/create">
    Create a data catalog from a CSV file or by entering columns manually.
  </Card>

  <Card title="Update data catalogs" icon="arrows-rotate" href="/vantage/documentation/skill-designer/document/using-data-catalogs/update">
    Update a data catalog by uploading a CSV file through the UI or via an SFTP shared folder.
  </Card>

  <Card title="Data catalogs and the Vantage API" icon="code" href="/vantage/documentation/skill-designer/document/using-data-catalogs/use-with-api">
    List, inspect, update, reindex, and delete data catalog records via the Vantage API.
  </Card>

  <Card title="Create data catalog lookup rules" icon="circle-check" href="/vantage/documentation/skill-designer/document/rule-verification/setting-lookup-rules">
    Verify extracted document fields against data catalog records using exact or fuzzy matching.
  </Card>

  <Card title="Role-based access control" icon="user-shield" href="/vantage/documentation/tenant-admin/tenant-management/role-based-access">
    The roles required to create, update, or use data catalogs in a tenant.
  </Card>
</CardGroup>