WorkflowDefinition
    graph       (WorkflowGraph SqlBackendKey SqlBackendKey)
    scope       WorkflowInstanceScope'
    name        (CI Text)
    UniqueWorkflowDefinition name scope

WorkflowInstance
    definition  WorkflowDefinitionId
    graph       (WorkflowGraph SqlBackendKey SqlBackendKey)  -- FileId, UserId
    scope       (WorkflowInstanceScope SqlBackendKey SqlBackendKey SqlBackendKey)  -- TermId, SchoolId, CourseId
    name        (CI Text)
    category    (CI Text) Maybe
    UniqueWorkflowInstance name scope

WorkflowWorkflow
    instance    WorkflowInstanceId
    graph       (WorkflowGraph SqlBackendKey SqlBackendKey)  -- FileId, UserId
    initUser    UserId Maybe
    initTime    UTCTime
    state       (WorkflowState SqlBackendKey SqlBackendKey)  -- FileId, UserId
    currentNode WorkflowGraphNodeLabel