# Message attributes

Each SNS message contains a collection of key-value pairs called **message attributes**. The attributes of a particular message depend on the action that is performed on the entity.  Message attributes are used to filter messages to an SNS topic's subscribers, to ensure a subscriber only receives the events in which they are interested. Below are the message attributes included for the following types of messages:

* [Entity - Create, Update, Delete](#entity-create-update-delete)
* [Entity - Action Executed](#entity-action-executed)
* [Entity - Availability Changed](#entity-availability-changed)
* [Relationship - Create, Update, Delete](#relationship-create-update-delete)

## Entity - Create, Update, Delete

| Attribute Name | Data Type | Description                                            |
| -------------- | --------- | ------------------------------------------------------ |
| action         | string    | *created, updated, deleted*                            |
| charTypeID     | number    | The char type ID of the entity.                        |
| templateID     | number    | The template ID of the entity.                         |
| statusID       | number    | The status ID of the entity.                           |
| userID         | number    | The ID of the user that took the action on the entity. |

## Entity - Action Executed

| Attribute Name   | Data Type | Description                                            |
| ---------------- | --------- | ------------------------------------------------------ |
| action           | string    | *action-executed*                                      |
| charTypeID       | number    | The char type ID of the entity.                        |
| templateID       | number    | The template ID of the entity.                         |
| statusID         | number    | The status ID of the entity.                           |
| userID           | number    | The ID of the user that took the action on the entity. |
| executedActionID | number    | The ID of the action executed.                         |
| processID        | number    | The ID of the workflow process for the entity.         |

## Entity - Availability Changed

| Attribute Name | Data Type | Description                                            |
| -------------- | --------- | ------------------------------------------------------ |
| action         | string    | *availability-changed*                                 |
| charTypeID     | number    | The char type ID of the entity.                        |
| templateID     | number    | The template ID of the entity.                         |
| statusID       | number    | The status ID of the entity.                           |
| userID         | number    | The ID of the user that took the action on the entity. |

## Relationship - Create, Update, Delete

| Attribute Name     |        | Description                                                  |
| ------------------ | ------ | ------------------------------------------------------------ |
| action             | string | *created, updated, deleted*                                  |
| charTypeID         | number | *0*                                                          |
| relationshipTypeID | number | The type ID of the relationship.                             |
| parentCharTypeID   | number | The char type ID of the parent entity.                       |
| childCharTypeID    | number | The char type ID of the child entity.                        |
| parentTemplateID   | number | The template ID of the parent entity.                        |
| childTemplateID    | number | The template ID of the child entity.                         |
| parentStatusID     | number | The status ID of the parent entity.                          |
| childStatusID      | number | The status ID of the child entity.                           |
| userID             | number | The ID of the user that took the action on the relationship. |