Create a Data Extension

What is a Data Extension?

  • A Data Extension is a table within the Marketing Cloud that stores data.  It’s similar to a list and that it is a container for your data, however, the ability to perform sophisticated operations skyrockets when using data extensions
  • Think of it as a container of data that looks exactly like a spreadsheet
  • It contains column headers called fields and rows of data
  • Data extensions allows you to emulate a relational database
  • You can create separate data extensions that are truly standalone and with the power of Marketing Cloud and AMPScript, those data extensions can relate to one another

What type of data can be stored in a Data extension?

  • Any data that is needed for your email campaign can be stored in a data extension
  • Examples include, but not limited to:
    • Product Catalog
    • Info from Commerce
    • Warehouse information
    • Data on your subscribers
    • Data captured from web analytics
    • HTML Code
    • Image URLS
    • Product SKUs
  • The Marketing Cloud essentially becomes your data warehouse, similar to a bucket, for all the data needed to deploy your email campaigns

What is a Subscriber?

  • A subscriber is a person who has opted-in to receive communications from your organization
  • Simple put, it’s an email address that you are sending email to
  • In the marketing cloud, you will be able to import data that consists of subscribers email addresses and personal profile information.  This information will be used in email campaigns to send timely and relevant email communications


  • We know that an attribute is data about the subscriber such as:
    • Subscriber Key
    • Email Address
    • First Name
    • Sport
    • Gender
    • Loyalty Points
  • Email address is a required attribute.  It is the default unique identifier within the email application
  • A unique identifier is the item that identifies the subscriber in the system
  • Each unique ID can only exist one time and all data about an individual subscriber is stored on that unique identifier
    • Data such as:
    • Profile Attributes
    • Tracking results
    • Email history
  • This is important because each unique ID can only exist one time so you may want to use something else other than the email address.  That’s where the subscriber key comes in

What is a Subscriber Key?

  • A subscriber key is a unique identifier that identifies a subscriber in the system
  • Required with Enterprise 2.0 accounts
  • When Subscriber Key is populated by a value that is not an email address, an email address can exist multiple times in the data extension
  • Subscriber Keys can be populated by:
    • An Email Address
      • If an email address is the unique identifier, each email can only exist once
    • Another Unique Number
      • If a subscriber key is populated by another unique identifier, each subscriber key can only exist once and the same email address can exist multiple times
  • Each subscriber cannot exist in the system without an email address

What is a Sendable Data Extension?

  • A Sendable Data Extension is a data extension that contains email addresses for the subscribers you wish to send emails to
  • A sendable data extension must contain a field to hold an email address.
  • The data type for the field must be email address
  • The data extension must also be flagged as “Used for Sending”

What is a Send Relationship?

  • A Send Relationship defines a field in the Sendable data Extensions to map to Subscriber Key in All Subscribers when sending

What is All Subscribers?

  • The All Subscribers list is a master database of all subscribers that have been sent an email
  • Keeps the status of the subscriber
  • There is one All Subscribers per account
  • If a subscriber is unsubscribed in the All Subscribers list, that subscriber will be unsubscribed from all lists and groups
  • When a subscriber is set back to active in the All Subscribers list, the subscriber will also need to be set back to active on each list and group they would like to be active on
  • A subscriber can be unsubscribed on lists and groups and still be active on the All Subscribers list

Types of Data Extensions

  1. Standard Data Extension
    • A standard data extension allows you to create custom fields to store data
  2. Filtered Data Extension
    • A filtered data extension is generated by filtering fields, measures, and filters for sendable data extensions from a source data extension
  3. Random Data Extension
    • Random data extension allows you to randomly select subscribers from a source data extension
    • Only 12 random data extensions can be created at one time

Campaign Association

  • You can associate your data extension to a campaign

Data Retention Policy

  • The default retention setting is set to “off”.  If you have this feature enabled, the data admin user for your Marketing Cloud account can enable or change the data retention policy for new data extensions
  • By default, the data extension retention policy deletes unused data extensions after 6 months
    • Deletion process runs nightly
    • You must set these options when creating the data extension
    • You cannot modify the delete settings for an existing data extension
    • You can modify the deletion period for existing data extensions

Primary Key

  • The Primary Key determines whether the system considers this field to be the primary key of the table
  • If you select this checkbox, the system requires that the value in this field be unique so it can use this field to uniquely identify a row
  • If you do not select this checkbox, the system does not require the value in this field to be unique


  • A nullable value means that it is not a required field

Default Value

  • Setting a default value to a field gives the field a value if nothing was specified

How can data be used?

  • Individualize the Content of the Email using:
    • Personalization Strings
      • Are tags that let you insert any of the attributes in your account such as subscriber name and emails
      • Can be used in the subject line or content body of the email
      • Example: Dear %%FirstName%%
    • Dynamic Content
      • Is content that is displayed in a content box according the rules that you defined based on the subscribers attributes or data extension column values
      • You can ensure that a more tailored message is reaching your target audience
      • Can be used in any type of email other than text based email messages
      • Example:
        • If Gender = Male, show Male Content Box
        • If Gender = Female, show Female Content Box
  • Target a specific segment of subscribers using:
    • Segmentation
      • Is to separate subscribers by attributes/fields
      • Is the key to delivering targeted relevant messages that speak to your subscribers specific needs, wants and interests
      • Example:
        • If Attribute/Field = X, place into segment A
        • If Sport = Hiking, place into Hiking filtered data extension


  • A data extension can contain subscriber data
  • Multiple data extensions can be created based on your email campaigns
  • A subscriber can exist on multiple data extensions
  • When a subscriber is sent an email, their email address is automatically added to All Subscribers which is the master database for your account
  • Data can be used for personalization, dynamic content and segmentation



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