RavenDb facet search in string array field with wildcard - ravendb

Question

Is it possible to have a RavenDb faceted search, in a string[] field, where I would want to show facets (counts) for only values starting with a particular string, rather a range?
I'll try to explain myself better to with a simple example, imagine having an index with the below entries
ID | Values
-------------------------
1 | CatPersian, CatNormal, DogLabrador
2 | CatPersian, Camel, DogPoodle
3 | CatNormal, CatBengali, DogNormal
4 | DogNormal
I would perform a query on the above documents, and the Facet search would include a range of 'Cat*', on the 'Values' field. Is this possible? Then, I would get a result based on just the different values for cats, like:
CatPersian [2]
CatNormal [2]
CatBengali [1]

Answer 1

Yes, you can do that. Index the array, and then just use facets normally.
Let's see the full example. You have the following documents:
{
"Name": "John",
"FavoriteAnimals": [
"Cats",
"Dogs",
"Snails"
],
"#metadata": {
"#collection": "Kids"
}
}
{
"Name": "Jane",
"FavoriteAnimals": [
"Cats",
"Rabits"
],
"#metadata": {
"#collection": "Kids"
}
}
Now, you create the following index:
from k in docs.Kids
from animal in k.FavoriteAnimals
select new { Animal = animal }
And run this query:
from index 'YourIndex'
where startsWith(Animal , 'ca')
select facet('Animal')
And the result will be:
{
"Name": "Animal",
"Values": [
{
"Count": 2,
"Range": "cats"
}
]
}
Alternatively, you can use this index:
from k in docs.Kids
select new { k.FavoriteAnimals }
And run this query:
from index 'YourIndex'
where startsWith(FavoriteAnimals , 'ca')
select facet('FavoriteAnimals')
The difference here is that you'll get all matches for the documents that have a match.
So in this case
{
"Name": "Animal",
"Values": [
{
"Count": 2,
"Range": "cats"
},
{
"Count": 1,
"Range": "dogs"// also, snails, rabbits
}
]
}