generated: '2026-07-19'
method: searched
source: https://docs.flywheel.io/user/navigate/user_the_flywheel_hierarchy/
docs: https://docs.flywheel.io/user/navigate/user_the_flywheel_hierarchy/
notes: >-
  Flywheel enforces a fixed container hierarchy for all research data. Captured
  from the Flywheel hierarchy documentation. Derived from docs (no public
  OpenAPI); relationships reflect the documented strict parent-child structure.
entities:
  - name: Group
    description: Top-level organizational container; owns one or more Projects.
  - name: Project
    description: A research project within a Group; contains Subjects.
  - name: Subject
    description: A study participant/subject within a Project; contains Sessions.
  - name: Session
    description: A single imaging session/visit for a Subject; contains Acquisitions.
  - name: Acquisition
    description: One imaging series/sequence within a Session; holds image Files.
  - name: File
    description: A data file (DICOM, NIfTI, etc.) attached to a container.
  - name: Analysis
    description: Outputs and inputs of a gear run, attachable to Sessions/Acquisitions/Projects.
  - name: Gear
    description: A ready-to-run plug-in application (classification, QA, conversion, pipelines).
relationships:
  - from: Group
    to: Project
    type: has_many
  - from: Project
    to: Subject
    type: has_many
    via: parent
  - from: Subject
    to: Session
    type: has_many
    via: parent
  - from: Session
    to: Acquisition
    type: has_many
    via: parent
  - from: Acquisition
    to: File
    type: has_many
  - from: Session
    to: Analysis
    type: has_many
  - from: Analysis
    to: Gear
    type: belongs_to
    via: gear
constraints:
  - A Group cannot directly parent an Acquisition; the full chain Project > Subject > Session must exist.