# Creating and Viewing a List Attribute

A list attribute (or buffer attribute) is an array of values. such as "products viewed in the last 10 hours" and "products purchased in the most recent transaction."

The length is limited by bye size, the number of elements, and time. Your customer requirements and contractual agreements determine this size.

This topic includes:

## Prerequisites

To create a list attribute, you must have [*Full*](/products/control-panel/security/policies/policy-based-data-workbench-permissions) for all parent segments.

## Limitations

* The maximum amount of elements allowed is 100.
* The maximum sliding duration is 60 days.


## Create a List Attribute

1. Open TD Console.
2. Navigate to the **Data Workbench**.
3. Select a parent segment to create a list attribute.
4. Select **Real-time Configuration**.
5. Select the **Attributes** tab, and then select **Add Attributes**.
6. Select **List**.


![](/assets/creating-a-list-of-attributes-2024-07-03.a5580730e1344f9475d3471c819f892ef878a2644ac2da7c481f00376e8e4789.cf3845cb.png)

Review the information in the following table to complete the form.

| Field Name | Description | Required |
|  --- | --- | --- |
| Name | Enter a name for your attribute list. | X |
| System ID
 | Create a system ID for a unique list attribute name. A system ID is a string that starts with an alphabet or underscore (*) and is optionally followed by an alphanumeric and (*). No spaces or special characters are allowed. This field can not be updated once defined. The system ID is case-sensitive.
**Example** *systemID_lst_01*
 | X
 |
| Description | (Optional) Enter a description of your list attribute. |  |
| Key event | Select a key event for your list attribute. For more information, see [Configuring Event Definitions](/products/customer-data-platform/real-time/creating-a-real-time-configuration#configure-event-definitions). Optionally, add filters. | X |
| Item ID | Select a key column for the attribute.Avoid using a profile key as an item ID.
 | X |
| Additional properties | Select one or more additional properties to identify other columns for your list attribute. |  |
| Item duration | Select the amount of sliding time duration of the data in the list. As time progresses, new data is added, and old data beyond the duration is removed from the list attribute. The maximum value is 60 days. | X |
| Maximum no. of elements | Select the maximum number of items/elements in the list attribute array. As new elements get added, old elements beyond the limit will be removed from the list. The maximum value is 100. | X |
| Attributes
 | Select **+ Add aggregation** to add attributes to your list attribute. Complete the following fields for each aggregation:
- **Name**: Enter a unique name for the aggregation. The aggregation will be displayed as *list name* - *aggregation name*.
- **System ID**: Create a unique system ID for the aggregation. A system ID is a string that starts with an alphabet or underscore (*) and is optionally followed by an alphanumeric and (*). The system ID is case-sensitive.
- **Aggregation Type**: Select the aggregation type from the provided list. The following types are available:
  - First (string)
  - Last (string)
  - Sum (number)
  - Min (number)
  - Max (number)
  - Distinct List: Use this type to create a list of item IDs or properties that can be used as an attribute.
- **Property**: Select the property (one of the columns specified in the "Additional properties" field or "Item Id") to associate with the aggregation type.

- Each list attribute supports a maximum of 50 aggregations.
- Ordering of the list is based on the Timestamp.

 |  |
| Advanced Settings |  |  |
| Additional rules
 | Select **+ Add event** to create additional rules. With these rules you can define events that can affect the values in the list attribute:
- **Remove:** Define event and filter rules that will remove a value from the list attribute
- **Clear**: Select an event and filter rules that will clear the full list attribute.

**Examples**
Event **remove_cart** will remove items from the cart. Event **purchase** will clear the list of products in the cart.
 |  |


An aggregation must be specified for a list attribute to be accessed in real-time journeys and activations.

1. Select **Create**.


## View List Attributes

After you have created one or more list attributes, you can view them in the Data Workbench.

1. Open TD Console.
2. Navigate to the **Data Workbench** >**Parent Segments.**
3. Select a parent segment.
4. Select the ellipses in the row where the list attribute is displayed.


![](/assets/creating-and-viewing-a-list-attribute-2024-07-29-3.c8e40e43aa323d833628456d4bfd7c5c104edd0bdec90497531410a6b458b7bd.cf3845cb.png)

1. Select **View Details**.


See also [Real-time Attribute FAQs](/products/customer-data-platform/real-time/real-time-attribute-faqs).