Distinct Attribute

The value of a field whose attribute is set as a distinct attribute will always be unique in the returned documents.

In such a case, there will never be two, or more, occurrences of the same value of that field in the different documents returned by MeiliSearch.

When multiple documents have the same value for a distinct attribute, MeiliSearch returns the first one after applying ranking rules. If documents are equivalent in terms of ranking, MeiliSearch returns the first in terms of internal_id.

Example

Suppose you have an e-commerce dataset. For an index that contains information about jackets, you may have several identical items in different variations (color or size).

As shown below, you have 3 documents that contain information about the same jacket. One of the jackets is brown, one is black, and the last one is blue.

  1. [
  2.   {
  3.     "id": 1,
  4.     "description": "Leather jacket",
  5.     "brand": "Lee jeans",
  6.     "color": "brown",
  7.     "product_id": "123456"
  8.   },
  9.   {
  10.     "id": 2,
  11.     "description": "Leather jacket",
  12.     "brand": "Lee jeans",
  13.     "color": "black",
  14.     "product_id": "123456"
  15.   },
  16.   {
  17.     "id": 3,
  18.     "description": "Leather jacket",
  19.     "brand": "Lee jeans",
  20.     "color": "blue",
  21.     "product_id": "123456"
  22.   }
  23. ]

You may want to ignore the different colors of an item. To do so, you can set product_id as a distinctAttribute.

  1. curl
  2.   -X POST 'http://localhost:7700/indexes/jackets/settings' \
  3.   --data '{ "distinctAttribute": "product_id" }'
  1. client.index('jackets').updateSettings({ distinctAttribute: 'product_id' })
  1. client.index('jackets').update_settings({'distinctAttribute': 'product_id'})
  1. $client->index('jackets')->updateDistinctAttribute('product_id');
  1. client.index('jackets').update_distinct_attribute('product_id')
  1. client.Settings("jackets").UpdateDistinctAttribute("product_id")
  1. let jackets: Index = client.get_index("jackets").await.unwrap();
  2. let progress: Progress = jackets.set_distinct_attribute("product_id").await.unwrap();

By setting product_id as a distinct attribute, search requests will never return more than one jacket with the same product_id.

For this example, querying for lee leather jacket would only return the first document found. The response could look like this:

  1. {
  2.   "hits": [
  3.     {
  4.       "id": 1,
  5.       "description": "Leather jacket",
  6.       "brand": "Lee jeans",
  7.       "color": "brown",
  8.       "product_id": "123456"
  9.     }
  10.   ],
  11.   "offset": 0,
  12.   "limit": 20,
  13.   "nbHits": 1,
  14.   "exhaustiveNbHits": false,
  15.   "processingTimeMs": 0,
  16.   "query": "lee leather jacket"
  17. }