Relationship Field
The Relationship Field is one of the most powerful fields Payload features. It provides for the ability to easily relate documents together.
The Relationship field is used in a variety of ways, including:
- To add
Product
documents to anOrder
document - To allow for an
Order
to feature aplacedBy
relationship to either anOrganization
orUser
collection - To assign
Category
documents toPost
documents
To add a Relationship Field, set the type
to relationship
in your Field Config:
Config Options
Option | Description |
---|---|
name * | To be used as the property name when stored and retrieved from the database. More |
relationTo * | Provide one or many collection slug s to be able to assign relationships to. |
filterOptions | A query to filter which options appear in the UI and validate against. More. |
hasMany | Boolean when, if set to true , allows this field to have many relations instead of only one. |
minRows | A number for the fewest allowed items during validation when a value is present. Used with hasMany . |
maxRows | A number for the most allowed items during validation when a value is present. Used with hasMany . |
maxDepth | Sets a maximum population depth for this field, regardless of the remaining depth when this field is reached. Max Depth |
label | Text used as a field label in the Admin Panel or an object with keys for each language. |
unique | Enforce that each entry in the Collection has a unique value for this field. |
validate | Provide a custom validation function that will be executed on both the Admin Panel and the backend. More |
index | Build an index for this field to produce faster queries. Set this field to true if your users will perform queries on this field's data often. |
saveToJWT | If this field is top-level and nested in a config supporting Authentication, include its data in the user JWT. |
hooks | Provide Field Hooks to control logic for this field. More details. |
access | Provide Field Access Control to denote what users can see and do with this field's data. More details. |
hidden | Restrict this field's visibility from all APIs entirely. Will still be saved to the database, but will not appear in any API or the Admin Panel. |
defaultValue | Provide data to be used for this field's default value. More |
localized | Enable localization for this field. Requires localization to be enabled in the Base config. |
required | Require this field to have a value. |
admin | Admin-specific configuration. More details. |
custom | Extension point for adding custom data (e.g. for plugins) |
typescriptSchema | Override field type generation with providing a JSON schema |
virtual | Provide true to disable field in the database. See Virtual Fields |
* An asterisk denotes that a property is required.
Admin Options
The customize the appearance and behavior of the Relationship Field in the Admin Panel, you can use the admin
option:
The Relationship Field inherits all of the default options from the base Field Admin Config, plus the following additional options:
Property | Description |
---|---|
isSortable | Set to true if you'd like this field to be sortable within the Admin UI using drag and drop (only works when hasMany is set to true ). |
allowCreate | Set to false if you'd like to disable the ability to create new documents from within the relationship field. |
allowEdit | Set to false if you'd like to disable the ability to edit documents from within the relationship field. |
sortOptions | Define a default sorting order for the options within a Relationship field's dropdown. More |
Sort Options
You can specify sortOptions
in two ways:
As a string:
Provide a string to define a global default sort field for all relationship field dropdowns across different collections. You can prefix the field name with a minus symbol ("-") to sort in descending order.
Example:
This configuration will sort all relationship field dropdowns by "fieldName"
in ascending order.
As an object :
Specify an object where keys are collection slugs and values are strings representing the field names to sort by. This allows for different sorting fields for each collection's relationship dropdown.
Example:
In this configuration:
- Dropdowns related to
pages
will be sorted by"fieldName1"
in ascending order. - Dropdowns for
posts
will use"fieldName2"
for sorting in descending order (noted by the "-" prefix). - Dropdowns associated with
categories
will sort based on"fieldName3"
in ascending order.
Note: If sortOptions
is not defined, the default sorting behavior of the Relationship field dropdown will be used.
Filtering relationship options
Options can be dynamically limited by supplying a query constraint, which will be used both for validating input and filtering available relationships in the UI.
The filterOptions
property can either be a Where
query, or a function returning true
to not filter, false
to
prevent all, or a Where
query. When using a function, it will be
called with an argument object with the following properties:
Property | Description |
---|---|
relationTo | The collection slug to filter against, limited to this field's relationTo property |
data | An object containing the full collection or global document currently being edited |
siblingData | An object containing document data that is scoped to only fields within the same parent of this field |
id | The id of the current document being edited. id is undefined during the create operation |
user | An object containing the currently authenticated user |
Example
You can learn more about writing queries here.
Bi-directional relationships
The relationship
field on its own is used to define relationships for the document that contains the relationship field, and this can be considered as a "one-way" relationship. For example, if you have a Post that has a category
relationship field on it, the related category
itself will not surface any information about the posts that have the category set.
However, the relationship
field can be used in conjunction with the Join
field to produce powerful bi-directional relationship authoring capabilities. If you're interested in bi-directional relationships, check out the documentation for the Join field.
How the data is saved
Given the variety of options possible within the relationship
field type, the shape of the data needed for creating
and updating these fields can vary. The following sections will describe the variety of data shapes that can arise from
this field.
Has One
The most simple pattern of a relationship is to use hasMany: false
with a relationTo
that allows for only one type
of collection.
The shape of the data to save for a document with the field configured this way would be:
When querying documents in this collection via REST API, you could query as follows:
?where[owner][equals]=6031ac9e1289176380734024
.
Has One - Polymorphic
Also known as dynamic references, in this configuration, the relationTo
field is an array of Collection slugs that
tells Payload which Collections are valid to reference.
The shape of the data to save for a document with more than one relationship type would be:
Here is an example for how to query documents by this data (note the difference in referencing the owner.value
):
?where[owner.value][equals]=6031ac9e1289176380734024
.
You can also query for documents where a field has a relationship to a specific Collection:
?where[owners.relationTo][equals]=organizations
.
This query would return only documents that have an owner relationship to organizations.
Has Many
The hasMany
tells Payload that there may be more than one collection saved to the field.
To save the to hasMany
relationship field we need to send an array of IDs:
When querying documents, the format does not change for arrays:
?where[owners][equals]=6031ac9e1289176380734024
.
Has Many - Polymorphic
Relationship fields with hasMany
set to more than one kind of collections save their data as an array of objects—each
containing the Collection slug
as the relationTo
value, and the related document id
for the value
:
Querying is done in the same way as the earlier Polymorphic example:
?where[owners.value][equals]=6031ac9e1289176380734024
.
Querying and Filtering Polymorphic Relationships
Polymorphic and non-polymorphic relationships must be queried differently because of how the related data is stored and
may be inconsistent across different collections. Because of this, filtering polymorphic relationship fields from the
Collection List admin UI is limited to the id
value.
For a polymorphic relationship, the response will always be an array of objects. Each object will contain
the relationTo
and value
properties.
The data can be queried by the related document ID:
?where[field.value][equals]=6031ac9e1289176380734024
.
Or by the related document Collection slug:
?where[field.relationTo][equals]=your-collection-slug
.
However, you cannot query on any field values within the related document. Since we are referencing multiple collections, the field you are querying on may not exist and break the query.