DPP does not create a database, nor does it store image edits in a sidecar file. Because Canon (of course) knows the complete code for its proprietary Raw format, CR2, it can safely insert and save the edit instructions internally, within the Raw file. Adobe can only do this to a Raw file in its own format, DNG. In DPP's case that metadata section is called VRP and in LR's (or ACR's) case it is labeled XMP; however, in both cases the image data section remains completely untouched. But because LR cannot read the VRD data, much less convert it to CR compatible edit settings, you can edit and alter a CR2 from here to next week and beyond in DPP and save (overwrite) the file thus saving the DPP edits in the VRD, but when you import that same file into LR and go to Develop it's like starting again at the beginning, at Adobe defaults. And going the other way, LR to DPP, is the same. The only way to transfer image editing from one to the other is to "bake" the edited version into a rendered 16 bit Tif, saved/exported from one and opened/imported in the other.
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