Skip to content

Flywheel Hierarchy

Fundamentals

Flywheel Organization

In Flywheel, data is organized in "Containers". Containers are essentially objects (as in, object-oriented programming kind of objects) that contain actual data files, as well as metadata and custom information about the container or files themselves.

There are 8 containers used in Flywheel: Five of them are primarily hierarchical containers used for organization of data:

  1. Group
  2. Project
  3. Subject
  4. Session
  5. Acquisition

In these five containers, the parent/child order is rigidly enforced. For example, a "Group" container cannot directly have an acquisition container attached as a child. Instead, it must have a "Project" child, which must have a "Subject" child, which must have a "Session" child, which then can have an "Acquisition" child.

In addition to these five containers, there are two "sub-containers" that can belong to most containers regardless of their level in the hierarchy.

  1. File
  2. Analysis

Finally, there is the last container, which is used to organize running tasks (gears) on the site:

  1. Job

Each container has its own metadata attributes associated with it. Some are shared across multiple (or all) containers, while others are unique to a specific container type.

Additionally, users can upload custom information to any container as a form of additional metadata fields.

Groups

The Group Container has the following attributes:

  • _id
  • created
  • editions
  • label
  • modified
  • permissions
  • providers
  • tags

Group containers cannot have Files, Analyses, or Jobs associated with them.

Group containers may have child Projects:

>>> Group1
   ├─ Project 1
   ├─ Project 2
   └─ Project 3

Projects

The Project Container has the following attributes

  • _id
  • analyses
  • created
  • description
  • editions
  • files
  • group
  • info
  • info_exists
  • label
  • modified
  • notes
  • parents
  • permissions
  • providers
  • public
  • tags
  • templates

Note that analyses and files are attributes of the Project container.

Project containers may have Files and Analyses associated with them.

Project containers may have child Subjects:

>>> Project 1
     ├─ [analyses]
     │    └─Analysis1
     │       ├─ Analysis File1
     │       └─ Analysis File2
     │
     ├─ [files]
     │    └─ Project File1
     ├─ Subject 1
     └─ Subject 2

Subjects

The Subject Container has the following attributes:

  • _id
  • age
  • analyses
  • code
  • cohort
  • created
  • ethnicity
  • files
  • firstname
  • info
  • info_exists
  • label
  • lastname
  • master_code
  • modified
  • notes
  • parents
  • permissions
  • project
  • public
  • race
  • sex
  • species
  • strain
  • tags
  • type

Note that analyses and files are attributes of the Subject container.

The project attribute is not referring to a "child" Project that belongs to the subject, it instead is a reference to the Subject container's parent Project.

Subject containers may have Files and Analyses associated with them.

Subject containers may have child Sessions:

>>> Subject 1
     ├─ [analyses]
     │    └─Analysis1
     │       ├─ Analysis File1
     │       └─ Analysis File2
     │
     ├─ [files]
     │    └─ Subject File1
     ├─ Session 1
     └─ Session 2

Sessions

The Session Container has the following attributes:

  • _id
  • age
  • analyses
  • created
  • files
  • group
  • info
  • info_exists
  • label
  • modified
  • notes
  • operator
  • parents
  • permissions
  • project
  • project_has_template
  • public
  • satisfies_template
  • subject
  • tags
  • timestamp
  • timezone
  • uid
  • weight

Note that analyses and files are attributes of the Session container.

The group, project, and subject attributes are not referring to a "child" container that belongs to the session, it instead is a reference to the session's parent containers.

Session containers may have Files and Analyses associated with them.

Session containers may have child Acquisitions:

>>> Session 1
     ├─ [analyses]
     │    └─Analysis1
     │       ├─ Analysis File1
     │       └─ Analysis File2
     │
     ├─ [files]
     │    └─ Session File1
     ├─ Acquisition 1
     └─ Acquisition 2

Acquisitions

The Acquisition Container has the following attributes:

  • _id
  • analyses
  • collections
  • created
  • files
  • info
  • info_exists
  • label
  • modified
  • notes
  • parents
  • permissions
  • public
  • session
  • tags
  • timestamp
  • timezone
  • uid

Note that analyses and files are attributes of the Acquisition container.

The session attribute is not referring to a "child" Session that belongs to the acquisition, it instead is a reference to the acquisition's parent container.

Acquisition containers may have Files and Analyses associated with them:

>>> Acquisition 1
     ├─ [analyses]
     │    └─Analysis1
     │       ├─ Analysis File1
     │       └─ Analysis File2
     │
     └─ [files]
          └─ Acquisition File1

The files attached to an acquisition are the files that you actually see in Flywheel on a typical session view:

image

For all other containers, files will appear under the "Attachments" category when viewing the container's info:

image