> ## Documentation Index
> Fetch the complete documentation index at: https://docs.a7manager.se/llms.txt
> Use this file to discover all available pages before exploring further.

# Measurements tables

> Measurement types, thresholds and recorded values.

Measurement types, thresholds and recorded values.

A **✓** in the Null column means the field is optional. Constraint definitions are
reproduced verbatim from PostgreSQL, so they are the exact rule being enforced.
Descriptions come from the models; a blank one means the field carries no
description yet, not that it has no meaning.

### `measurements_measurementtype`

| Column                 | Type                     | Null | Default | Description                                                                                                                  |
| ---------------------- | ------------------------ | :--: | ------- | ---------------------------------------------------------------------------------------------------------------------------- |
| `id`                   | uuid                     |      |         |                                                                                                                              |
| `created_at`           | timestamptz              |      |         |                                                                                                                              |
| `updated_at`           | timestamptz              |      |         |                                                                                                                              |
| `code`                 | varchar(50)              |      |         | Short identifier, e.g. 'WHEEL\_DIAMETER'                                                                                     |
| `name`                 | varchar(255)             |      |         | Display name, e.g. 'Wheel diameter'                                                                                          |
| `unit`                 | varchar(20)              |      |         | Display unit, e.g. 'mm', 'h', 'kg'                                                                                           |
| `progression_rule`     | varchar(20)              |      |         | Expected direction of consecutive measurements; enforced at import unless action\_code is in reset\_action\_codes.           |
| `allowed_action_codes` | character varying(50)\[] |      |         | Closed set of accepted action codes. Empty = no enforcement.                                                                 |
| `reset_action_codes`   | character varying(50)\[] |      |         | Action codes that exempt the progression rule and start a new analytics segment. Must be a subset of allowed\_action\_codes. |
| `project_id`           | uuid                     |      |         | Parent project for multi-tenancy                                                                                             |

<Accordion title="Constraints — 1 unique, 1 foreign key, 1 primary key">
  | Kind        | Name                                       | Definition                            |
  | ----------- | ------------------------------------------ | ------------------------------------- |
  | Foreign key |                                            | `(project_id) REFERENCES project(id)` |
  | Primary key |                                            | `(id)`                                |
  | Unique      | `unique_measurement_type_code_per_project` | `(project_id, code)`                  |
</Accordion>

### `measurements_measurementthreshold`

| Column                | Type          | Null | Default | Description                                                       |
| --------------------- | ------------- | :--: | ------- | ----------------------------------------------------------------- |
| `id`                  | uuid          |      |         |                                                                   |
| `created_at`          | timestamptz   |      |         |                                                                   |
| `updated_at`          | timestamptz   |      |         |                                                                   |
| `nominal_value`       | numeric(10,2) |   ✓  |         | New/healthy reading.                                              |
| `min_value`           | numeric(10,2) |   ✓  |         | Wear/replacement threshold (and import floor).                    |
| `max_value`           | numeric(10,2) |   ✓  |         | Upper sanity bound (and import ceiling).                          |
| `component_type_id`   | uuid          |      |         | The component type these bounds apply to.                         |
| `measurement_type_id` | uuid          |      |         | The kind of measurement these bounds apply to.                    |
| `reframing_task_id`   | uuid          |   ✓  |         | Preventive-reframing task that caps the wheel reframing forecast. |

<Accordion title="Constraints — 1 unique, 3 foreign keys, 1 primary key">
  | Kind        | Name                        | Definition                                                          |
  | ----------- | --------------------------- | ------------------------------------------------------------------- |
  | Foreign key |                             | `(component_type_id) REFERENCES assets_componenttype(id)`           |
  | Foreign key |                             | `(measurement_type_id) REFERENCES measurements_measurementtype(id)` |
  | Foreign key |                             | `(reframing_task_id) REFERENCES servicebook_maintenancetask(id)`    |
  | Primary key |                             | `(id)`                                                              |
  | Unique      | `unique_threshold_per_pair` | `(measurement_type_id, component_type_id)`                          |
</Accordion>

### `measurements_measurement`

| Column                | Type          | Null | Default | Description                                                       |
| --------------------- | ------------- | :--: | ------- | ----------------------------------------------------------------- |
| `id`                  | uuid          |      |         |                                                                   |
| `created_at`          | timestamptz   |      |         |                                                                   |
| `updated_at`          | timestamptz   |      |         |                                                                   |
| `position`            | varchar(50)   |   ✓  |         | Slot position from CSV; cross-checked against active mount.       |
| `measured_at`         | timestamptz   |      |         | When the reading was captured.                                    |
| `performance_km`      | int           |   ✓  |         | Vehicle reading at measurement time.                              |
| `operating_hours`     | int           |   ✓  |         | Vehicle reading at measurement time.                              |
| `value`               | numeric(10,2) |      |         | The reading itself; unit comes from measurement\_type.unit.       |
| `action_code`         | varchar(50)   |   ✓  |         | Action code from source system.                                   |
| `action_description`  | varchar(255)  |   ✓  |         |                                                                   |
| `reason_code`         | varchar(50)   |   ✓  |         | Free-text reason code (not validated).                            |
| `reason_description`  | varchar(255)  |   ✓  |         |                                                                   |
| `notes`               | text          |      |         |                                                                   |
| `external_system_id`  | varchar(100)  |      |         | Unique identifier from source measurement system.                 |
| `external_updated_at` | timestamptz   |      |         | Last modification timestamp from the master system.               |
| `component_id`        | uuid          |   ✓  |         | Component this reading was captured against (resolved at import). |
| `project_id`          | uuid          |      |         | Parent project for multi-tenancy                                  |
| `vehicle_id`          | uuid          |   ✓  |         | Vehicle this reading was captured against (resolved at import).   |
| `measurement_type_id` | uuid          |      |         | The kind of reading this row captures.                            |

<Accordion title="Constraints — 1 check, 1 unique, 4 foreign keys, 1 primary key">
  | Kind        | Name                                         | Definition                                                          |
  | ----------- | -------------------------------------------- | ------------------------------------------------------------------- |
  | Check       | `measurement_must_have_vehicle_or_component` | `(((vehicle_id IS NOT NULL) OR (component_id IS NOT NULL)))`        |
  | Foreign key |                                              | `(component_id) REFERENCES assets_component(id)`                    |
  | Foreign key |                                              | `(measurement_type_id) REFERENCES measurements_measurementtype(id)` |
  | Foreign key |                                              | `(vehicle_id) REFERENCES assets_vehicle(id)`                        |
  | Foreign key |                                              | `(project_id) REFERENCES project(id)`                               |
  | Primary key |                                              | `(id)`                                                              |
  | Unique      | `unique_measurement_external_id_per_project` | `(external_system_id, project_id)`                                  |
</Accordion>