<ReferenceManyCount>

When you need to render the number of records related to another record via a one-to-many relationship (e.g. the number of comments related to a post), use the <ReferenceManyCount> component. It calls dataProvider.getManyReference() with the pagination parameter set to retrieve no data - only the total number of records.

ReferenceManyCount

Usage

Use <ReferenceManyCount> as a regular Field in a <Datagrid> or <SimpleShowLayout> - or anywhere inside a RecordContext. You must set the reference and target props to match the relationship:

  • reference is the name of the related resource to fetch (e.g. comments)
  • target is the name of the field in the related resource that points to the current resource (e.g. post_id)
import { 
    ChipField,
    Datagrid,
    DateField,
    List,
    NumberField,
    ReferenceArrayField,
    ReferenceManyCount,
    SingleFieldList,
    TextField,
} from 'react-admin';

export const PostList = () => (
    <List>
        <Datagrid>
            <TextField source="id" />
            <TextField source="title" />
            <DateField source="published_at" sortByOrder="DESC" />
            <ReferenceManyCount
                label="Nb comments"
                reference="comments"
                target="post_id"
                link
            />
            <NumberField source="views" sortByOrder="DESC" />
            <ReferenceArrayField
                label="Tags"
                reference="tags"
                source="tags"
            >
                <SingleFieldList>
                    <ChipField source="name.en" size="small" />
                </SingleFieldList>
            </ReferenceArrayField>
        </Datagrid>
    </List>
)

Tip: If you need to count all the records of a given resource, use the <Count> component instead.

Props

Prop Required Type Default Description
reference Required string - Name of the related resource to fetch (e.g. comments)
target Required string - Name of the field in the related resource that points to the current one.
filter Optional Object - Filter to apply to the query.
link Optional bool false If true, the count is wrapped in a <Link> to the filtered list view.
resource Optional string - Resource to count. Default to the current ResourceContext
sort Optional { field: string, order: 'ASC' or 'DESC' } { field: 'id', order: 'DESC' } The sort option sent to getManyReference
timeout Optional number 1000 Number of milliseconds to wait before displaying the loading indicator.

<ReferenceManyCount> also accepts the common field props.

Additional props are passed to the underlying Material UI <Typography> element.

filter

If you want to count the number of records matching a given filter, pass it as the filter prop. For example, to count the number of comments already published:

<ReferenceManyCount 
    label="Comments"
    reference="comments"
    target="post_id"
    filter={{ is_published: true }}
/>

If you want to wrap the count in a <Link> to the list view filtered for the current record, pass true to the link prop.

<ReferenceManyCount 
    label="Comments"
    reference="comments"
    target="post_id"
    link
/>

When used in conjunction to the filter prop, the link will point to the list view with the filter applied.

<ReferenceManyCount 
    label="Comments"
    reference="comments"
    target="post_id"
    link 
    filter={{ is_published: true }}
/>

reference

The reference prop is required and must be the name of the related resource to fetch. For instance, to fetch the number of comments related to the current post:

<ReferenceManyCount 
    label="Comments"
    reference="comments"
    target="post_id"
/>

resource

By default, the <ReferenceManyCount> component uses the current ResourceContext, so you don’t need to pass the resource prop to count the number of records in the current Resource. If you want to count a different resource, pass it as the resource prop.

<ReferenceManyCount 
    label="Comments"
    reference="comments"
    target="post_id"
    resource="posts"
/>

sort

If you want to customize the sort options passed to getManyReference (for instance because your relation table does not have an id column), you can pass a custom sort prop:

<ReferenceManyCount 
    label="Comments"
    reference="comments"
    target="post_id"
    sort={{ field: 'custom_id', order: 'ASC' }}
/>

target

The target prop is required and must be the name of the field in the related resource that points to the current one. For instance, when fetching the number of comments related to the current post, if a comment relates to a post via a post_id foreign key, you must set the target prop to post_id:

<ReferenceManyCount 
    label="Comments"
    reference="comments"
    target="post_id"
/>

timeout

The <ReferenceManyCount> component displays a loading indicator after 1 second. This is useful to avoid displaying a loading indicator when the count is retrieved in a few milliseconds. You can change this delay by passing a timeout prop.

<ReferenceManyCount 
    label="Comments"
    reference="comments"
    target="post_id"
    timeout={500}
/>