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Location QuerySet Examples

These examples are written for the backend Django models that power the locations endpoints exposed by the SDK. They use the exact schema and join/filter paths that are visible in this workspace through LocationsAPI, its docstrings, and its tests.

The server-side model declarations are not checked into this workspace, so reverse-manager examples assume Django's default accessors where no custom related_name is visible. The forward paths and filter names are the ones exercised by the SDK today.

Shell Setup

Run the snippets in python manage.py shell or python manage.py shell_plus.

# Core imports for the locations app.
from django.db.models import Count

from locations.models import AssetLocation, Location, ProjectSite

Data Model Overview

  • ProjectSite is the root object for a site such as the real Nobelwind record with slug="nobelwind".
  • Location stores the shared location row and has a foreign key to ProjectSite through projectsite.
  • AssetLocation is a Django multi-table-inheritance child of Location; its primary key is the parent Location row.
  • The SDK confirms the site-to-location join path by sending projectsite__title=... when LocationsAPI.get_assetlocations() is scoped to a project site.

Entity Relationship Diagram

erDiagram
    ProjectSite {
        int id PK
        string slug
        string title
        int created_by
        int modified_by FK
    }

    Location {
        int id PK
        int created_by FK
        int modified_by FK
        int projectsite_id FK
        string title
        string slug
    }

    AssetLocation {
        int location_id PK
    }

    ProjectSite ||--o{ Location : projectsite_id
    Location ||--|| AssetLocation : inherits

Query Flow

flowchart LR
    ProjectSite[ProjectSite]
    Location[Location]
    AssetLocation[AssetLocation]

    ProjectSite -->|projectsite FK| Location
    Location -->|multi-table inheritance| AssetLocation

Basic Queries

# List every project site row.
ProjectSite.objects.all()

# Fetch the real Nobelwind record by slug.
ProjectSite.objects.filter(slug="nobelwind")

# Inspect the base location rows that belong to Nobelwind.
Location.objects.filter(projectsite__slug="nobelwind")

# Query only the inherited asset-location rows for the same site.
AssetLocation.objects.filter(projectsite__slug="nobelwind")

# Pull the parent site in the same query for each location row.
Location.objects.select_related("projectsite")

# AssetLocation inherits Location, so inherited Location fields are still
# available and can be joined with select_related.
AssetLocation.objects.select_related("projectsite").filter(
    projectsite__slug="nobelwind"
)

Reverse Relations

# Start from one project site and walk back to its base locations.
projectsite = ProjectSite.objects.get(slug="nobelwind")
projectsite.location_set.all()

# Walk from the parent Location row to the AssetLocation child row.
location = Location.objects.select_related("projectsite").get(
    projectsite__slug="nobelwind",
    title="BBA01",
)
location.assetlocation

Inheritance-Aware Queries

# Multi-table inheritance lets you filter AssetLocation through inherited
# Location columns such as projectsite and title.
AssetLocation.objects.filter(
    projectsite__slug="nobelwind",
    title__startswith="BB",
)

# When you need both the site and its asset count, annotate at the root.
ProjectSite.objects.annotate(location_count=Count("location")).filter(
    slug="nobelwind"
)

Prefetching Traversals

# Prefetch every base location row for the Nobelwind site.
ProjectSite.objects.filter(slug="nobelwind").prefetch_related("location_set")

# Prefetch the inherited asset rows when you know each Location will be
# accessed as an AssetLocation later in the request.
Location.objects.filter(projectsite__slug="nobelwind").prefetch_related(
    "assetlocation"
)

SDK Alignment

The SDK uses Django-style backend filters directly. These two examples are equivalent in intent.

# Backend QuerySet executed in the Django project.
AssetLocation.objects.filter(projectsite__title="Nobelwind")

# Equivalent SDK call from the external client.
from owi.metadatabase.locations.io import LocationsAPI

api = LocationsAPI(token="your-api-token")

# The SDK turns this into the backend filter `projectsite__title=Nobelwind`.
api.get_assetlocations(projectsite="Nobelwind")

You can also forward extra Django-style filters through the SDK.

from owi.metadatabase.locations.io import LocationsAPI

api = LocationsAPI(token="your-api-token")

# Additional keyword arguments are passed through as backend filters.
api.get_assetlocations(
    projectsite="Nobelwind",
    title__startswith="BB",
)

Live Route Validation

The live dev list route was validated on 2026-03-23 with authenticated GET requests to /api/v1/locations/routes/projectsite/.

  • Confirmed working list filter: title
  • Confirmed examples: title=Belwind, title=Nobelwind
  • Confirmed empty-result behavior: title=not-a-site returns []
  • Observed as ineffective on this list route: slug, id, projectsite

That matters because the QuerySet examples above describe backend model access, while the list route exposes a narrower public filter surface. For live route calls, prefer the exact title filter.

from owi.metadatabase.io import API

api = API(
    api_root="https://owimetadatabase-dev.azurewebsites.net/api/v1/locations/routes/",
    token="your-api-token",
)

api.send_request("projectsite/", {"title": "Nobelwind"}).json()