SearchableCharField in Django, GIN Index for case-insensitive search

models.py

from django.db import models
from django.contrib.postgres.indexes import GinIndex
from django.db.models.functions import Lower


class SearchableCharField(models.CharField):
    def contribute_to_class(self, cls, name, **kwargs):
        super().contribute_to_class(cls, name, **kwargs)

        # Add a GIN index with trigram operations for fast search
        cls._meta.indexes.extend([
            GinIndex(fields=[name], opclasses=["gin_trgm_ops"]),
            # For case-insensitive search
            GinIndex(fields=[Lower(name)], name=f"{name}_lower_trgm_idx", opclasses=["gin_trgm_ops"]),
        ])



# Use like this
class Author(models.Model):
    full_name = SearchableCharField(max_length=100)

# Use in a query with __icontains
Author.objects.filter(full_name__icontains="Pedro") 
# SELECT * FROM author WHERE full_name ILIKE '%Pedro%';