Django Queryset icontains() method not returning exact match

Question

I am trying to filter a model, by passing the text query, and checking if any of the fields contains the value that matches exactly or partially to the given text query.

So let's say I have a model named Sample, which contains char fields ["name", "state", "type"]. Assuming one of the model object has a value of state to set as "barely alive"

I looked at the methods described in the following django doc: https://docs.djangoproject.com/en/2.1/ref/contrib/postgres/search/

I want to retrieve that object by using any of "barely","arely" or "barely alive"as a text query.

I initially tried something like Sample.objects.annotate(search=SearchVector(*list_of_fields)).filter(search__icontains=query_text)

Above line will however, will not return a correct queryset if I pass a full text barely alive as a query text and only work when partial text such as barely or alive is passed.

So I then tried Sample.objects.annotate(search=SearchVector(*list_of_fields)).filter(search=query_text).filter(search__icontains=query_text) But then it returns an empty Queryset.

What am I missing here?

Answer 1

PostgreSQL's full text search has quite a few intricacies with regard to partial matching, see e.g. here and here.

However, if you can get by with an OR query as you attempted, it's not difficult, you just need an appropriately constructed Q object instead of two chained filter calls (because filter chaining uses AND, not OR). So instead of

.filter(search=query_text).filter(search__icontains=query_text)

use

.filter(Q(search=query_text) | Q(search__icontains=query_text))