Canonical event model

HOME > [SNOWPLOW TECHNICAL DOCUMENTATION](Snowplow technical documentation) > [Storage](storage documentation) > Canonical Event Model

# Canonical data structure

1. Overview
2. The Snowplow canonical data structure: understanding the individual fields
3. A note about data storage formats

## 1. Overview

In order to analyse Snowplow data, it is important to understand how it is structured. We have tried to make the structure of Snowplow data as simple, logical, and easy-to-query as possible.

• Single table Snowplow data is stored in a single, "fat" (many columns) table. We call this the Snowplow events table
• Each line represents one event. Each line in the table represents a single event, be that a page view, add to basket, play video, like etc.
• Immutable log. The Snowplow data table is designed to be immutable: the data in each line should not change over time. Data points that we would expect to change over time (e.g. what cohort a particular user belongs to, how we classify a particular visitor) can be derived from Snowplow data. However, our recommendation is that these derived fields should be defined and calculated at analysis time, stored in a separate table and joined to the Snowplow events table when performing any analysis
• Structured events. Snowplow explicitly recognises particular events that are common in web analytics (e.g. page views, transactions, ad impressions) as 'first class citizerns'. We have a model for the types of fields that may be captured when those events occur, and specific columns in the database that correspond to those fields
• Unstructured events. We intend to build out support for unstructured events. (So that Snowplow users will be able to construct their own arbritary JSONs of fields for their own event types.) When supported, these JSONs will be stored as-is e.g. in a single 'unstructured event' column in Hive
• Whilst some fields are event specific (e.g. tr_city representing the city in a delivery address for an online transaction), others are platform specific (e.g. page_url for events that occur on the web) and some are relevant across platforms, devices and events (e.g. dt and tm, the date and time an event occurs, or app_id, the application ID).
• Evolving over time. We are building out the canonical data structure to make its understanding of individual event-types richer (more events, more fields per events) and to support more platforms. This needs to be done in a collaborative way with the Snowplow community, so that the events and fields that you need to track can easily be accommodated in this data structure. Please [get in touch] (Talk-to-us) to discuss your ideas and requirements

## 2. The Snowplow canonical data structure: understanding the individual fields

• 2.1 Common fields (platform and event independent)
  • 2.1.1 Application fields
  • 2.1.2 Date / time fields
  • 2.1.3 Event / transaction fields
  • 2.1.4 Snowplow version fields
  • 2.1.5 User-related fields
  • 2.1.6 Device and operating system fields
  • 2.1.7 Location fields
• 2.2 Platform-specific fields
  • 2.2.1 Web-specific fields
• 2.3 Event-specific fields
  • 2.3.1 Event vendor
  • 2.3.2 Page views
  • 2.3.3 Page pings
  • 2.3.4 Link clicks
  • 2.3.5 Ad impressions
  • 2.3.6 Ecommerce transations
  • 2.3.7 Social events
  • 2.3.8 Item views
  • 2.3.9 Error tracking
  • 2.3.10 Custom structured events
  • 2.3.11 Custom unstructured events

### 2.1 Common fields (platform and event independent) #### 2.1.1 Application fields

Field	Type	Description	Reqd?	Impl?	Example
app_id	text	Application ID	Yes	Yes	'angry-birds'
platform	text	Platform	Yes	Yes	'web'

The application ID is used to distinguish different applications that are being tracked by the same Snowplow stack.

The platform ID is used to distinguish the same app running on different platforms e.g. iOS vs web.

Back to top.

#### 2.1.2 Date / time fields

Field	Type	Description	Reqd?	Impl?	Example
collector_dt	date	Date event was recorded by the collector	Yes	Yes	'2013-01-31'
collector_tm	time	Time event was recorded by the collector	Yes	Yes	'11:35:30'
dvce_dt	date	Date event was recorded on the client device	No	Yes	'2013-02-05'
dvce_tm	time	Time event was recorded on the client device	No	Yes	'11:27:45'
dvce_epoch	int	Milliseconds since the epoch (1/1/1970) on the client device	No	Yes	1361495852452
os_timezone	text	Client operating system timezone	No	Yes	'Europe/London'

We are currently considering extending the date / time fields to store the date / time as recorded on the client and server in separate fields. See issue 149 for details.

Back to top.

#### 2.1.3 Event / transaction fields

Field	Type	Description	Reqd?	Impl?	Example
event	text	The type of event recorded	Yes	Yes	'page_view'
event_id	text	A UUID for each event	Yes	Yes	'c6ef3124-b53a-4b13-a233-0088f79dcbcb'
txn_id	int	Transaction ID set client-side, used to de-dupe records	No	Yes	421828

A complete list of event types is given [here] (#event).

Back to top.

#### 2.1.4 Snowplow version fields

Field	Type	Description	Reqd?	Impl?	Example
v_tracker	text	Tracker version	Yes	Yes	'no-js-0.1.0'
v_collector	text	Collector version	Yes	Yes	'clj-tomcat-0.1.0', 'cf'
v_etl	text	ETL version	Yes	Yes	'serde-0.5.2'

Back to top.

#### 2.1.5 User-related fields

Field	Type	Description	Reqd?	Impl?	Example
user_id	text	Unique ID set by business	No	Yes	'[email protected]'
domain_userid	text	User ID set by Snowplow using 1st party cookie	No	Yes	'bc2e92ec6c204a14'
network_userid	text	User ID set by Snowplow using 3rd party cookie	No	Yes	'ecdff4d0-9175-40ac-a8bb-325c49733607'
user_ipaddress	text	Ueser IP address	No	Yes	'92.231.54.234'
domain_sessionidx	int	A visit / session identifier	No	Yes	3
user_dimension1 -> user_dimension10	text	Custom dimensions that are set at a user-level	No	No	'member'
visit_dimension1 -> visit_dimension10	text	Custom dimensions that are set at a session-level	No	No	-

Back to top.

#### 2.1.6 Device and operating system fields

Field	Type	Description	Reqd?	Impl?	Example
useragent	text	Raw useragent	Yes	Yes
dvce_type	text	Type of device	No	Yes	'Computer'
dvce_ismobile	boolean	Is the device mobile?	No	Yes	1
dvce_screenheight	int	Screen height in pixels	No	Yes	1024
dvce_screenwidth	int	Screen width in pixels	No		1900
os_name	text	Name of operating system	No	Yes	'Android'
os_family	text	Operating system family	No	Yes	'Linux'
os_manufacturer	text	Company responsible for OS	No	Yes	'Apple'

Back to top.

#### 2.1.7 Location fields

Note: none of these fields have been implemented yet.

Field	Type	Description	Reqd?	Impl?	Example
geo_country	text	ISO 3166-1 code for the country the visitor is located in	No	No	'GB'
geo_region	text	ISO-3166-2 code for country region the visitor is in	No	No	'Devon'
geo_city	text	City the visitor is in	No	No	'London'
geo_zipcode	text	Postcode the visitor is in	No	No	'N3'
geo_latitude	text	Visitor location latitude	No	No	59.666702
geo_longitude	text	Visitor location longitude	No	No	10.800003

### 2.2 Platform-specific fields

Currently the only platform supported is web. However, as we build trackers for more platforms (e.g. iOS, Windows 8) we would expect to add platforms that are specific to each of these platforms.

#### 2.2.1 Web-specific fields

Field	Type	Description	Reqd?	Impl?	Example
Page fields
page_urlscheme	text	Scheme aka protocol	Yes	Yes	'https'
page_urlhost	text	Host aka domain	Yes	yes	'“www.snowplowanalytics.com'
page_urlport	int	Port if specified, 80 if not	Yes	80
page_urlpath	text	Path to page	No	Yes	'/product/index.html'
page_urlquery	text	Querystring	No	Yes	'id=GTM-DLRG'
page_urlfragment	text	Fragment aka anchor	No	Yes	'4-conclusion'
page_title	text	Web page title	No	Yes	'Using ChartIO to visualize and interrogate Snowplow data - Snowplow Analytics'
refr_urlscheme	text	Referer scheme	No	Yes	'http'
refr_urlhost	text	Referer host	No	Yes	'www.bing.com'
refr_urlport	int	Referer port	No	Yes	80
refr_urlpath	text	Referer page path	No	Yes	'/images/search'
refr_urlquery	text	Referer URL querystring	No	Yes	'q=psychic+oracle+cards'
refr_urlfragment	text	Referer URL fragment	No	Yes
refr_source	text	Name of referer if recognised	No	Yes	'Bing images'
refr_term	text	Keywords if source is a search engine	No	Yes	'psychic oracle cards'
Document fields
doc_charset	text	The page’s character encoding	No	Yes	, 'UTF-8'
doc_width	int	The page's width in pixels	No	Yes	1024
doc_height	int	The page's height in pixels	No	Yes	3000
page_type	text	Category of page	No	No	'product', 'catalogue'
page_dimension1 -> page_dimension10	text	Custom dimensions associated with this web page	No	No
page_metric1 -> page_metric10	decimal	Custom metric values with the loading of this web page	No	No	3.5
Marketing / traffic source fields
mkt_medium	text	Type of traffic source	No	Yes	'cpc', 'affiliate', 'organic', 'social'
mkt_source	text	The company / website where the traffic came from	No	Yes	'Google', 'Facebook'
mkt_term	text	Any keywords associated with the referrer	Yes	No	'new age tarot decks'
mkt_content	text	The content of the ad. (Or an ID so that it can be looked up.)	No	Yes	13894723
mkt_campaign	text	The campaign ID	No	Yes	'diageo-123'
mkt_referrerurl	text	The URL that drove the user to the website being tracked at the session start	No	No	'http://news.ycombinator.com/newest'
Browser fields
user_fingerprint	int	A user fingerprint generated by looking at the individual browser features	No	Yes	2161814971
connection_type	text	Type of internet connection	No	No	-
cookie	boolean	Does the browser support persistent cookies?	No	Yes	1
br_lang	text	Language the browser is set to	No	Yes	'en-GB'
br_features	array	An array of browser features that the browser supports	No	Yes	['pdf', 'java', 'fla']
br_colordepth	int	Bit depth of the browser color palette	No	Yes	24
br_jsversion	text	Javascript version	No	No	-
br_viewheight	int	Viewport height	No	No	1000
br_viewwidth	int	Viewport width	No	No	1000

See issue 94 for more details on br_windowheight and br_windowwidth.

Back to top.

### 2.3 Event-specific fields

Snowplow includes specific fields to capture data associated with specific events.

2.3.1 Event vendor

Going forwards, we plan to enable users to define their own events and data model associated for each event. When that is enabled, it will be possible to distinguish between events defined by different companies using the event_vendor field:

Field	Type	Description	Reqd?	Impl?	Example
event_vendor	text	Company that developed the event model	Yes	Yes	'com.snowplowanalytics'

Note that to date, all event types have been defined by Snowplow. Also note that event_vendor values follow the Java package naming convention.

Snowplow currently supports (or will support in the near future) the following event types:

	Event type	Value of event field in model
2.3.2	Page views	'page_view'
2.3.3	Page pings	'page_ping'
2.3.4	Link clicks	'link_click'
2.3.5	Ad impressions	'ad_impression'
2.3.6	Ecommerce transactions	'transaction' and 'transaction_item'
2.3.7	Social events	'social'
2.3.8	Item views	'item_view'
2.3.9	Errors	'error'
2.3.10	Custom structured events	'struct'
2.3.11	Custom unstructured events	'unstruct'

Details of which fields are available for which events are given below:

#### 2.3.2 Page views

There are currently fields that are specific to page_view events: all the fields that are required are part of the standard fields available for any web-based event e.g. page_urlscheme, page_title.

Back to top.

#### 2.3.3 Page pings

There are four additional fields included with page pings that indicate how a user has scrolled over a web page since the last page ping:

Field	Type	Description	Reqd?	Impl?	Example
pp_xoffset_min	integer	Minimum page x offset seen in the last ping period	No	Yes	0
pp_xoffset_max	integer	Maximum page x offset seen in the last ping period	No	Yes	100
pp_yoffset_min	integer	Minimum page y offset seen in the last ping period	No	Yes	0
pp_yoffset_max	integer	Maximum page y offset seen in the last ping period	No	Yes	200

Back to top.

#### 2.3.3 Link clicks

This is not currently supported: we plan to add support shortly. For details see [issue 75] (https://github.com/snowplow/snowplow/issues/75).

Back to top.

#### 2.3.4 Ad impressions

Currently the following ad-impression specific fields are not included in the canonical event model. We need to implement them shortly. (See issue 129.)

Field	Type	Description	Reqd?	Impl?	Example
adi_bannerid	text	Banner ID	No	No	-
adi_campaignid	text	Campaign ID	No	No	-
adi_advertiserid	text	Advertiser ID	No	No	-
adi_userid	text	User ID (as set by the ad server)	No	No	-
adi_zoneid	text	Publisher / website zone ID	No	No	-

Back to top.

#### 2.3.5 Ecommerce transactions

There are a large number of fields specifically for transaction events.

Fields that start tr_ relate to the transaction as a whole. Fields that start ti_ refer to the specific item included in the transaction. (E.g. a product in the basket.) Single transactions typically span multiple lines of data: there will be a single line where event = transaction, where the tr_ fields are set, and multiple lines (one for each product included) where event = transaction_item and the ti_ fields are set.

Field	Type	Description	Reqd?	Impl?	Example
tr_orderid	text	Order ID	Yes	Yes	'#134'
tr_affiliation	text	Transaction affiliation (e.g. store where sale took place)	No	Yes	'web'
tr_total	decimal	Total transaction value	Yes	Yes	12.99
tr_tax	decimal	Total tax included in transaction value	No	Yes	3.00
tr_shipping	decimal	Delivery cost charged	No	Yes	0.00
tr_city	text	Delivery address, city	No	Yes	'London'
tr_state	text	Delivery address, state	No	Yes	'Washington'
tr_country	text	Delivery address, country	No	Yes	'France'
ti_orderid	text	Order ID	Yes	Yes	'#134'
ti_sku	text	Product SKU	Yes	Yes	'pbz00123'
ti_name	text	Product name	No	Yes	'Cone pendulum'
ti_category	text	Product category	No	Yes	'New Age'
ti_price	text	Product unit price	Yes	Yes	9.99
ti_quantity	text	Number of product in transaction	Yes	Yes	2

Back to top.

#### 2.3.6 Social events

This has not been developed yet. However, the intention is to build support for the following fields for use recording social events (e.g. likes, +1s).

Field	Type	Description	Reqd?	Impl?	Example
social_action	text	Social action performed	Yes	No	'like'
social_network	text	Social network	Yes	No	'Google+'
social_target	text	The object of the social action e.g. the music track liked, the tweet retweeted	No	No	'pbz00123'
social_pagepath	text	The URL of the page where the action occurred. This is generally the same as page_url, so does not need to be set	No	No	-

Back to top.

#### 2.3.7 Item views

This has not been implemented yet. The intention is to implement the following fields:

Field	Type	Description	Reqd?	Impl?	Example
item_id	text	Item ID e.g. SKU if item is a product	Yes	No	'pbz00123'
item_name	text	Item name or title	Yes	No	'Cone pendulum'
item_displayformat	text	Type of item listing. Used to distinguish views of a product summary (in a catalogue page) vs a detailed view (on the product page).	No	'summary-view'
item_rank	integer	Item rank (position if there is a list of items displayed on the page)	No	No	3
item_location	text	Location of the item on the web page	No	No	'div-cat-4'
item_dimension1 -> item_dimension10	text	Custom dimensions associated with each item / group of items	No	No	-
item_metric1 -> item_metric10	decimal	Custom metric values associated with the view of each item	No	No	-

For additional details see this gist and issue 113

Back to top.

#### 2.3.8 Error tracking

This has not been implemented yet.

Back to top.

#### 2.3.9 Custom structured events

If you wish to track an event that Snowplow does not recognise as a first class citizen (i.e. one of the events listed above), then you can track them using the generic 'custom structured events'. Currently there are five fields that are available to store data related to custom events: we plant to increase this to 25 in the near future:

Field	Type	Description	Reqd?	Impl?	Example
ev_category	text	Category of event	Yes	Yes	'ecomm', 'video'
ev_action	text	Action performed / event name	Yes	Yes	'add-to-basket', 'play-video'
ev_label	text	The object of the action e.g. the ID of the video played or SKU of the product added-to-basket	No	Yes	'pbz00123'
ev_property	text	A property associated with the object of the action	No	Yes	'HD', 'large'
ev_value	decimal	A value associated with the event / action e.g. the value of goods added-to-basket	No	Yes	9.99
ev_dimension1 -> ev_dimension10	text	Custom dimension fields that can be associated with the event	No	No	-
ev_metric1 -> ev_metric10	decimal	Custom metric fields that can be associated with the event	No	No	-

See issue 74 for additional information.

Back to top.

#### 2.3.10 Custom unstructured events

If you wish to track an event and do not want to map the data set you wish to capture every time that event occurs to the fields available in the Custom structured events listed above, you can alternatively store any JSON and associate it with an event name. Snowplow will store both fields (the event name and the associated JSON) directly in the events table. Note: this will only be available for querying in Hive (and other storage options that support arbritrary JSONs) - it will not be supported by Infobright, for example.

Field	Type	Description	Reqd?	Impl?	Example
ue_name	text	Unstructured event name	Yes	No	'Add-to-basket'
ue_json	json	A JSON of data associated with that specific event	Yes	No	{ 'product_sku': 'pbz00123', 'unit_price': 9.99 }

Back to top.

3. A note about storage data formats

• Currently, Snowplow data is stored in S3 (for processing in Apache Hive, Pig, and / or Mahout) and Infobright (for processing by any SQL-compatible analytics package).
• There are minor differences between the structure of data in both formats. These relate to data structures that Hive supports (e.g. maps, JSONs) that Infobright does not
• Nevertheless, the structure of both is similar: representing a fat table
• Going forwards our intention is to move the storage format for data on S3 from the current flatfile structure to Avro. This will become the 'canonical Snowplow data structure'. Other formats (e.g. Infobright, Redshift etc.) will simply be 'flattened' versions of the same data. We have outlined some of our plans in this blog post.

Back to top.