<ReferenceManyToManyInput>

This Enterprise Edition component allows to create, edit or remove relationships between two resources sharing an associative table. The changes in the associative table are sent to the dataProvider when the user submits the form, so that they can cancel the changes before submission.

Note: The <ReferenceManyToManyInput> cannot currently display multiple records with the same id from the end reference resource even though they might have different properties in the associative table.

Usage

Let’s imagine that you’re writing an app managing concerts for artists. The data model features a many-to-many relationship between the bands and venues tables through a performances associative table.

┌─────────┐       ┌──────────────┐      ┌───────────────┐
│ bands   │       │ performances │      │ venues        │
│---------│       │--------------│      │---------------│
│ id      │───┐   │ id           │   ┌──│ id            │
│ name    │   └──╼│ band_id      │   │  │ name          │
│         │       │ venue_id     │╾──┘  │ location      │
│         │       │ date         │      │               │
└─────────┘       └──────────────┘      └───────────────┘

In this example, bands.id matches performances.band_id, and performances.venue_id matches venues.id.

To let users edit the venues for given band in an <AutocompleteArrayInput>, wrap that input in a <ReferenceManyToManyInput> where you define the relationship via the reference, through and using props:

import { Edit, AutocompleteArrayInput, SimpleForm, TextInput } from 'react-admin';
import { ReferenceManyToManyInput } from '@react-admin/ra-relationships';

export const BandEdit = () => (
    <Edit>
        <SimpleForm>
            <TextInput source="name" />
            <ReferenceManyToManyInput
                reference="venues"
                through="performances"
                using="band_id,venue_id"
            >
                <AutocompleteArrayInput
                    label="Performances"
                    optionText="name"
                />
            </ReferenceManyToManyInput>
        </SimpleForm>
    </Edit>
);

<ReferenceManyToManyInput> expects a child that is an input allowing to select multiple values as child - like <AutocompleteArrayInput> in the example above. Other possible children are <SelectArrayInput>, <CheckboxGroupInput>, and <DualListInput>.

Note that although all possible child components support a defaultValue prop, it will only be applied on create views.

Tip: If you need to edit the fields of the associative table (e.g. the date in performances), you can use a <ReferenceManyInput> instead of <ReferenceManyToManyInput>.

You will need to let users select the related record (venues in the example above) via a <ReferenceInput>:

import {
    DateInput,
    Edit,
    ReferenceInput,
    SelectInput,
    SimpleForm,
    SimpleFormIterator,
    TextInput,
    required,
} from 'react-admin';
import { ReferenceManyInput } from '@react-admin/ra-relationships';

const BandEdit = () => (
    <Edit mutationMode="pessimistic">
        <SimpleForm>
            <TextInput source="name" />
            <ReferenceManyInput reference="performances" target="band_id">
                <SimpleFormIterator inline>
                    <DateInput source="date" />
                    <ReferenceInput reference="venues" source="venue_id">
                        <SelectInput optionText="name" />
                    </ReferenceInput>
                </SimpleFormIterator>
            </ReferenceManyInput>
        </SimpleForm>
    </Edit>
);

Limitation: <ReferenceManyToManyInput> cannot be used to filter a list.

Props

children

<ReferenceManyToManyInput> expects a select component as child, i.e. a component working inside a ChoiceContext. That means you can use a <SelectArrayInput>, or a <AutocompleteArrayInput>.

For instance, to allow user to choose performances using a <SelectArrayInput> instead of an <AutocompleteArrayInput>, you can write:

import React from 'react';
- import { Edit, AutocompleteArrayInput, SimpleForm, TextInput } from 'react-admin';
+ import { Edit, SelectArrayInput, SimpleForm, TextInput } from 'react-admin';
import { ReferenceManyToManyInput } from '@react-admin/ra-relationships';

export const BandEdit = () => (
    <Edit>
        <SimpleForm>
            <TextInput source="name" />
            <ReferenceManyToManyInput
                resource="bands"
                reference="venues"
                through="performances"
                using="band_id,venue_id"
            >
-                <AutocompleteArrayInput
-                    label="Performances"
-                    optionText="name"
-                />
+            <SelectArrayInput label="Performances" />
            </ReferenceManyToManyInput>
        </SimpleForm>
    </Edit>
);

filter

You can filter the records of the associative table (e.g. performances) using the filter prop. This filter is passed to the getManyReference() call.

<ReferenceManyToManyInput
    reference="venues"
    through="performances"
    using="band_id,venue_id"
    filter={{ date: '2018-08-31' }}
>
    {/* ... */}
</ReferenceManyToManyInput>

filterChoices

<ReferenceManyToManyInput> displays a list of possible values from the reference table (e.g. venues) as suggestions in the input. It uses the getList() dataProvider call to fetch these possible values.

You can filter the possible values of the reference table using the filterChoices prop. This filterChoices is passed to the getList() call.

<ReferenceManyToManyInput
    reference="venues"
    through="performances"
    using="band_id,venue_id"
    filterChoice={{ location: 'New York' }}
>
    {/* ... */}
</ReferenceManyToManyInput>

perPage

By default, react-admin displays at most 25 entries from the associative table (e.g. 25 performances). You can change the limit by setting the perPage prop:

<ReferenceManyToManyInput
    reference="venues"
    through="performances"
    using="band_id,venue_id"
    perPage={10}
>
    {/* ... */}
</ReferenceManyToManyInput>

perPageChoices

<ReferenceManyToManyInput> displays a list of possible values from the reference table (e.g. venues) as suggestions in the input. It uses the getList() dataProvider call to fetch these possible values.

By default, react-admin displays at most 25 possible values from the reference table (e.g. 25 venues). You can change the limit by setting the perPageChoices prop:

<ReferenceManyToManyInput
    reference="venues"
    through="performances"
    using="band_id,venue_id"
    perPageChoices={10}
>
    {/* ... */}
</ReferenceManyToManyInput>

reference

The name of the target resource to fetch.

For instance, if you want to display the venues of a given bands, through performances, the reference name should be venues:

<ReferenceManyToManyInput
    source="id"
    reference="venues"
    resource="bands"
    through="performances"
>
    {/* ... */}
</ReferenceManyToManyInput>

sort

By default, react-admin orders the possible values by id desc for the associative table (e.g. performances). You can change this order by setting the sort prop (an object with field and order properties) to be applied to the associative resource.

<ReferenceManyToManyInput
    reference="venues"
    through="performances"
    using="band_id,venue_id"
    sort={{ field: 'id', order: 'DESC' }}
>
    {/* ... */}
</ReferenceManyToManyInput>

sortChoices

By default, react-admin orders the possible values by id desc for the reference table (e.g. venues). You can change this order by setting the sortChoices prop (an object with field and order properties).

<ReferenceManyToManyInput
    reference="venues"
    through="performances"
    using="band_id,venue_id"
    sortChoices={{ field: 'id', order: 'DESC' }}
>
    {/* ... */}
</ReferenceManyToManyInput>

source

By default, ReferenceManyToManyField uses the id field as target for the reference. If the foreign key points to another field of your record, you can select it with the source prop:

<ReferenceManyToManyInput
    source="_id"
    reference="venues"
    resource="bands"
    through="performances"
>
    {/* ... */}
</ReferenceManyToManyInput>

through

You must specify the associative table name using the through prop.

<ReferenceManyToManyInput reference="venues" through="performances">
    {/* ... */}
</ReferenceManyToManyInput>

using

You can specify the columns to use in the associative using the using prop.

<ReferenceManyToManyInput
    reference="venues"
    through="performances"
    using="band_id,venue_id"
>
    {/* ... */}
</ReferenceManyToManyInput>

Limitations

• <ReferenceManyToManyInput> cannot be used inside an <ArrayInput>, a <ReferenceOneInput> or a <ReferenceManyInput>.
• <ReferenceManyToManyInput> does not support server side validation.

DataProvider Calls

When rendered, <ReferenceManyToManyInput> fetches the dataProvider three times in a row:

• once to get the records of the associative resource (performances in this case), using a getManyReference() call
• once to get the records of the reference resource (venues in this case), using a getMany() call.
• once to get the possible values of the reference resource (venues in this case) to show as suggestions in the input, using a getList() call

For instance, if the user edits the band of id 123, <ReferenceManyToManyInput> first issues the following query to the dataProvider:

dataProvider.getManyReference('venues', {
    target: 'band_id',
    id: 123,
});

Let’s say that the dataProvider returns the following response:

{
    "data": [
        { "id": 667, "band_id": 123, "venue_id": 732 },
        { "id": 895, "band_id": 123, "venue_id": 874 }
        { "id": 901, "band_id": 123, "venue_id": 756 }
    ],
    "total": 3
}

Then, <ReferenceManyToManyInput> issues a second query to the dataProvider:

dataProvider.getMany('venues', {
    ids: [732, 874, 756],
});

Which returns the following:

{
    "data": [
        { "id": 732, "name": "Madison Square Garden" },
        { "id": 874, "name": "Yankee Stadium" }
        { "id": 874, "name": "Barclays Center" }
    ]
}

That’s enough to display the current value in the input. But to display venues suggestions, the component makes a final call:

dataProvider.getList('venues', {
    sort: { field: 'id', order: 'DESC' },
    pagination: { page: 1, perPage: 25 },
    filter: {},
});

{
    "data": [
        { "id": 732, "name": "Madison Square Garden" },
        { "id": 874, "name": "Yankee Stadium" }
        { "id": 874, "name": "Barclays Center" }
        ...
    ],
    "total": 32
}

And that’s it for the display phase.

When the user submits the form, the save function compares the value of the <ReferenceManyToManyInput> (the list of relationships edited by the user) with the value previously returned by the dataProvider. Using a diffing algorithm, it deduces a list of insertions and deletions in the associative table, that are executed all at once.

For instance, let’s say that after displaying the venues 732 and 874 where bands 123 performs, the user removes venue 732, and adds venues 2 and 3. Upon submission, the dataProvider will detect removals and additions, and send the following queries:

dataProvider.delete('performances', {
    id: 667,
    previousData: { id: 667, band_id: 123, venue_id: 732 },
});
dataProvider.create('performances', {
    data: { band_id: 123, venue_id: 2 },
});
dataProvider.create('performances', {
    data: { band_id: 123, venue_id: 3 },
});