I'm trying to understand the hierarchy of UCM objects: UCM project, streams, baselines, composite baselines, VOB components, activities, change sets etc. Can you explain the hierarchy links between these objects? Can you provide a link to a good explanation? A visual diagram will be good as well
Thank you!
An UCM project is a container forn UCM Streams.
It contains at least one root stream (called "integration stream"), and several sub-streams.
See "Integration stream vs integration view in ClearCase" for more.
An UCM Stream is the representation of a "development effort", ie a way to share: - what you want to do (name of the Stream) - what you need to do it ("configuration" or list of Baselines for each Components)
A Baseline is a fixed version for a Component: all the files of a Component are labelled with the same label attached ot a Baseline.
A Component is a coherent set of file (even if you modify only one, you branch or label the all set).
You can have "component of components", which will trigger the creation of composite baselines:
See "What is composite baseline in UCM and when it will be used?" for more.
An activity is the list of versions you have modify for a given component, within a given Stream.
See "Clearcase: Activity dependencies for integration stream merging (patches)" for more.
See "How data flows in UCM projects"
来源：https://stackoverflow.com/questions/9976090/clearcase-ucm-hierarchy