« on: February 20, 2015, 12:36:42 PM »
Wrong. I guarantee I understand it way better than you do.
And you're wrong here also.A folder in Lightroom is a referenced folder on your hard drive.
No. That's just an attribute in the catalog that tells LR where the image file actually is - I too would not attempt to load large images into a SQLite database - other databases would handle it without any issue, but would be fairly more expensive and large to install - also storing them in the file sytem lets them available from other applications that can't access the LR database.
Can LR open a file folder and display images or work on them like for example Photoshop or DPP do? No, it can't. What happens if you move a file outside LR? It is no longer in sync, because now the stored attribute points to the wrong position.
Nor LR has any "folder" physical structure inside the database. From the LR perspective, the "folders" it displays are just a kind of collection, created on the image path attribute.
You're not saying something right. You're saying a folder in LR is a catalog. It isn't. It's what you said above - a database reference to the OS folder. That reference is in the catalog, the folder itself is not the catalog. The catalog only contains information about your images.
The issue came up when you said a folder was a catalog. It's not. An .lrcat file is a catalog (what Adobe calls their database). A folder is an OS folder (which itself is a conceptual thing, not a physical thing as well).
IIRC, all images (names & attributes) are in a single table within SQLite, all folders are in another table. The folders table then has a link to the filesystem folder, allowing it to of course work with removable media. The preview is another table - I dont think it's in the image table, but is referenced. It then links to the cache on the filesystem.
If anyone is interested, I used SQLite Manager within firefox to browse the table structure - which you can do in read only and thus preserve integrity. Take a copy if you are paranoid.
I wanted to find a quick way to hack out a list of images in a folder, and whether they were part of a stacked set of images so I could pump that list into either external HDR or Pano tools. I couldn't find anything, so I just figured out by looking at the tables and wrote a few bits of SQL to extract it.
Leaving the DB to handle things is indeed fine, if you prefer. Personally I use both. Folders is quickest when I want to get to a specific photo set. Keywords is easier to compare across multiple sets, collections if you dont have too many keywords. LR and I'm sure Aperture don't force any paradigm on you, they give you multiple options and let you do what works best for you.