What is Django Q objects for complex queries?

Django's Q objects allow building complex queries with OR conditions, negation, and combinations that can't be expressed by chaining .filter() calls (which always produce AND conditions). Q object basics: from django.db.models import Q # OR condition: articles = Article.objects.filter(Q(title__icontains="django") | Q(content__icontains="django")) # AND condition (same as chaining .filter()): articles = Article.objects.filter(Q(is_published=True) & Q(author=request.user)) # NOT condition: articles = Article.objects.filter(~Q(status="draft")) # Complex combination: articles = Article.objects.filter( (Q(title__icontains="python") | Q(tags__name="python")) & Q(is_published=True) & ~Q(author__is_banned=True) ). Dynamic query building: def search_articles(terms, published_only=True): q = Q() for term in terms: q |= Q(title__icontains=term) | Q(content__icontains=term) if published_only: q &= Q(is_published=True) return Article.objects.filter(q). F objects (field references): reference another field in the query: from django.db.models import F # Find articles where likes > views Article.objects.filter(likes__gt=F("views")) # Atomic field update: Article.objects.filter(pk=1).update(view_count=F("view_count") + 1) # Compare two fields: Article.objects.filter(updated_at__gt=F("created_at")). F objects prevent race conditions in updates — the increment happens at the database level atomically.