Dry ORM

Code

Result

no cache

from django.db import models, connection

class Employee(models.Model):
    business_subunit = models.CharField(max_length=50)
    stream = models.CharField(max_length=50)
    department = models.CharField(max_length=50)

class Meta:
        indexes = [
            models.Index(fields=["business_subunit"]),
            models.Index(fields=["business_subunit", "stream"]),
            models.Index(fields=["business_subunit", "stream", "department"]),
        ]

def run():
    # Bootstrap demo data
    for i in range(5):
        Employee.objects.create(
            business_subunit="BU1",
            stream="StreamA",
            department=f"Dept{i}",
        )
    for i in range(5):
        Employee.objects.create(
            business_subunit="BU2",
            stream="StreamB",
            department=f"Dept{i}",
        )

# Helper to run PostgreSQL EXPLAIN
    def explain(queryset):
        sql, params = queryset.query.sql_with_params()
        full_sql = "EXPLAIN " + sql
        with connection.cursor() as cursor:
            cursor.execute(full_sql, params)
            rows = cursor.fetchall()
        print(f"Query: {sql}")
        for row in rows:
            print(row[0])

# Queries to check index usage
    qs1 = Employee.objects.filter(business_subunit="BU1")
    explain(qs1)

qs2 = Employee.objects.filter(business_subunit="BU1", stream="StreamA")
    explain(qs2)

qs3 = Employee.objects.filter(business_subunit="BU1", stream="StreamA", department="Dept1")
    explain(qs3)

Output

No output.

Queries

Queries Q (0)

No queries.