#Dj-Adv

Django postgres full text search

• Unlike relational databases, full-text search is not standardized.
• There are several open-source options like ElasticSearch, Solr, and Xapian.
• For general uses
  • We can stick with the full-text search capabilities that many relational (like Postgres, MySQL, SQLite)
  • And non-relational databases (like MongoDB and CouchDB) offer.

Basic Search

• In Django you’ll typically start by performing search queries with contains or icontains for exact matches.
• The Q object can be used as well to add AND (&) or OR (|) logical operators.
• Limitations
  • Only exact match is shown –> similar words excluded
  • Stop word(article) all has same weight
  • complex lookups not possible

from django.db.models import Q

ProductDetail.objects.filter(Q(name__icontains=query))

Quote.objects.filter(Q(name__icontains=query) | Q(quote__icontains=query))

• Eg:
  • query = pony
  • then ponies != pony

The search lookup(Single Field Search)

• To use the search lookup, django.contrib.postgres must be in your INSTALLED_APPS.
• Used for Single Field Search
• Advantage
  • It takes similar words into account
    • ponies, pony

INSTALLED_APPS += ['django.contrib.postgres']

ProductDetail.objects.filter(name__search=query)

SearchVector

• To search against multiple fields and on related models, you can use the SearchVector

Entry.objects.annotate(search=SearchVector('body_text') + SearchVector('blog__tagline')).filter(search=query)

Quote.objects.annotate(search=SearchVector("name", "quote")).filter(search=query)

SearchQuery

SearchQuery translates the terms the user provides into a search query object that the database compares to a search vector. By default, all the words the user provides are passed through the stemming algorithms, and then it looks for matches for all of the resulting terms.