---
title: "attachment"
description: "Base StructureDefinition for Attachment Type: For referring to data content defined in other formats."
---

Base StructureDefinition for Attachment Type: For referring to data content defined in other formats.

## Source

| Model | Leg | Role |
|---|---|---|
| `Attachment` | FHIR | defines this table |
| `openEHR-EHR-CLUSTER.media_file.v1` | openEHR | merged in — Media file |

> This table is the union of 2 source models. Columns carrying a **From** value came from a model that merged into it, so the same row satisfies both specifications.

## Columns

| Column | Type | Null | Description | From | Source |
|---|---|---|---|---|---|
| `id` | `uuid primary key` | no | Attachment.id | — | — |
| `created_at` | `timestamptz` | no | Row creation timestamp. | — | — |
| `updated_at` | `timestamptz` | no | Row update timestamp; maintained by the application. | — | — |
| `created_by` | `text` | no | Actor who created the row. | — | — |
| `updated_by` | `text` | no | Actor who last updated the row. | — | — |
| `media_type` | `text` | no | Mime type of the content, with charset etc. | — | `Attachment.contentType` |
| `language` | `text` | yes | Human language of the content (BCP-47) | — | `Attachment.language` |
| `content` | `bytea` | yes | Data inline, base64ed | — | `Attachment.data` |
| `uri` | `text` | yes | Uri where the data can be found | — | `Attachment.url` |
| `size` | `integer` | yes | Number of bytes of content (if url provided) | — | `Attachment.size` |
| `hash` | `bytea` | yes | Hash of the data (sha-1, base64ed) | — | `Attachment.hash` |
| `title` | `text` | yes | Label to display in place of the data | — | `Attachment.title` |
| `creation` | `timestamptz` | yes | Date attachment was first created | — | `Attachment.creation` |
| `description` | `text` | yes | Description | `openEHR-EHR-CLUSTER.media_file.v1` | `/items[at0005]` |
| `comment` | `text` | yes | Comment | `openEHR-EHR-CLUSTER.media_file.v1` | `/items[at0007]` |
| `identifier_value`<br />`identifier_system` | text, text<br />`text`, `text` | yes | Identifier | `openEHR-EHR-CLUSTER.media_file.v1` | `/items[at0010]` |

## Constraints

```sql
check (identifier_system is null or identifier_value is not null)
check (num_nonnulls(content, uri) = 1)
```

## Referenced by

19 tables reference `attachment`, via `digital_representation`. The first 15 alphabetically:

- [`advance_care_directive`](/docs/tables/advance_care_directive) via `digital_representation`
- [`adverse_reaction_event_reaction_details`](/docs/tables/adverse_reaction_event_reaction_details) via `attachment_id`
- [`anatomical_location_multimedia_representation`](/docs/tables/anatomical_location_multimedia_representation) via `attachment_id`
- [`anatomical_location_circle_multimedia_representation`](/docs/tables/anatomical_location_circle_multimedia_representation) via `attachment_id`
- [`anatomical_location_relative_multimedia_representation`](/docs/tables/anatomical_location_relative_multimedia_representation) via `attachment_id`
- [`clinical_evidence_multimedia_representation`](/docs/tables/clinical_evidence_multimedia_representation) via `attachment_id`
- [`document_reference_content`](/docs/tables/document_reference_content) via `attachment`
- [`ecg_result_multimedia_representation`](/docs/tables/ecg_result_multimedia_representation) via `attachment_id`
- [`embryo_assessment_image_representation`](/docs/tables/embryo_assessment_image_representation) via `attachment_id`
- [`family_history_multimedia`](/docs/tables/family_history_multimedia) via `attachment_id`
- [`imaging_exam_result_report_representation`](/docs/tables/imaging_exam_result_report_representation) via `attachment_id`
- [`laboratory_test_result_multimedia_representation`](/docs/tables/laboratory_test_result_multimedia_representation) via `attachment_id`
- [`person`](/docs/tables/person) via `photo`
- [`procedure_multimedia`](/docs/tables/procedure_multimedia) via `attachment_id`
- [`pulse_oximetry_multimedia_image`](/docs/tables/pulse_oximetry_multimedia_image) via `attachment_id`