# About Lookup Fields

A _Lookup_ field propagates field values from a parent or referenced object to a child object, referring object, or document. This allows users to view relevant information from a related record. Lookup fields are never editable; they simply provide a way of displaying information from a related object record. You can search, filter, and report on lookup fields. They also allow more granularity for Dynamic Access Control. Lookup fields can exist on <a href="/en/gr/28740/#How_to_Add_Lookup_Fields">objects</a>
, <a href="/en/gr/62987/">raw objects</a>
, or <a href="/en/gr/5377/">documents</a>
.

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      <p><strong>Note</strong>: Lookup fields update asynchronously. For this reason, we do not recommend using them as conditions in time-based processes such as lifecycle entry actions or entry criteria. In addition, Lookup fields delete asynchronously, which may lead to a delay in deletion.</p>
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In Edit mode, the value of a Lookup field updates automatically when changing its parent or referenced object field.

## Object Relationships

Lookup fields on objects and raw objects must utilize an outbound (parent or referring) object relationship:

* **Example Parent-Child Relationship**: _Product_ is the parent object to _Marketing Campaign_. You could create a lookup field on the _Marketing Campaign_ object which pulls data from the _Product_ object, but you could not create a lookup field on the _Product_ object to pull data from the _Marketing Campaign_ object.
* **Example Reference Relationship**: This only applies to lookup fields on objects: The _Agency_ object has a referring relationship pointing to the _Marketing Campaign_ object. You could create a lookup field on _Agency_ to pull data from _Marketing Campaign_, but could not create a lookup field on _Marketing Campaign_ to pull data from the _Agency_ object.

If the source field you use for a lookup is a reference field, the object you're adding the field on inherits that relationship, which means that you can now use that relationship in reports and dashboards.

## Document-Object Relationships

Lookup fields on documents must utilize an object relationship created through an object-type document field. They cannot use a relationship created through a document reference field on an object.

* **Example Document-Object Relationship**: The _Product_ field on the _Promotional Piece_ document type creates a relationship between that document type and the _Product_ object. You could create a lookup field the document type which pulls data from the _Product Family_ field on the _Product_ object.

## Field Types & Restrictions

### Documents

When creating a lookup-type field on a document, the source field must have one of the following field types:

* Object
* Picklist (single-select and multi-select)

### Objects and Raw Objects

When creating a lookup-type field on an object or raw object, the source field must have one of the following field types:

* Object
* Picklist
* Text
* Long Text
* Rich Text
* Date
* DateTime
* Yes/No
* Number
* Currency

A lookup field on a document can use a multi-select field as _Lookup Object Field_, but not as _Lookup Source Field_.

Lookup fields also cannot use the following as source fields:

* Fields set up in Searchable Object Fields
* Inactive fields
* Other lookup-type fields


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      <p><strong>Note</strong>: If a Picklist field is used as the source field, you cannot use it as a controlling field in <a href="/en/gr/772652/">picklist dependencies</a>
.</p>
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## Audit Trail Tracking

Vault adds <a href="/en/gr/517/">audit trail</a>
 entries on corresponding object records in the following scenarios, except for lookup-type field on a raw object:

* The source value of a lookup field changes
* A lookup field is initialized and the lookup field value is set
* The reference object that a lookup field is based on changes

Vault adds audit trail entries corresponding to the last modified date on the record with the lookup field, which also updates under the above scenarios.

## Limits

Vault limits the number of lookup fields you can create in the following ways. These limits ensure that your Vault does not experience any performance issues.

### Lookup Fields on Objects {#object-limits}

The following limits apply to lookup fields created on an object:

| Limit Name | Limit | Description |
| --- | --- | --- |
| Maximum Lookup field relationships | 10 | This is the maximum number of lookup relationships an object can have. For example, if your _Product_ object has lookup relationships with ten (10) other objects, you will not be able to create a lookup relationship with an eleventh object. |
| Maximum Lookup fields per relationship | 20 | This is the maximum number of lookup fields that you can create for a lookup relationship. For example, if your _Product_ object has a lookup relationship with the _Generic Name_ object, you can only create 20 lookup fields on _Product_ that reference _Generic Name_ fields. |
| Maximum Lookup relationships to a source object | 8 | This is the maximum number of lookup relationships that can point to a single source object. For example, only eight relationships across all objects can have a lookup relationship that references the _Product_ object. You would not be able to create a ninth lookup relationship reference to _Product_ from any object. |

### Limits for Lookup Fields on Documents {#doc-limits}

The following limits apply to lookup-type document fields. Note that fields inherited from a higher level in the document type hierarchy count as a single field in these limit calculations.

| Limit Name | Limit | Description |
| --- | --- | --- |
| Lookup Fields per Object Reference Field | 7 | This is the maximum number of lookups that can rely on a single document-to-object reference field. For example, _Product_ is an object reference field on _Base Document_. This field creates a relationship between documents and the _Product_ object. You cannot create more than seven lookup fields that use this field to point to the _Product_ object. If a document type has two separate relationships to the same object (_Product_ and _Secondary Product_), Vault calculates this limit separately for each.|
| Lookup Fields per Source Field | 7 | This is the maximum number of lookup fields that can point to the same source field on the source object, across the entire Vault. For example, you cannot create more than seven lookup fields that get their value from the _Generic Name_ field on the _Product_ object. |
|  Lookup Fields per Source Object | 7 | This is the maximum number of lookup fields that can point to any source fields on a given object, across the entire Vault. For example, _Product_ and _Secondary Product_ are object reference fields on _Base Document_, both pointing to the _Product_ object. You cannot create more than seven lookup fields that use these two document-to-object relationships because they point to the same source object (_Product_).|