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Because I am learning QGIS and I had to delete records in a attribute table, I made a copy (project > save as > saving as 'project_copy' before deleting attributes. To be safe...

So I deleted the attributes in the project_copy. But to my surprise, I see that the deleted attributes are also deleted in the original project!? There seems to be a link between both projects although I didn't ask for...

Did I really lose the deleted attributes?

Is there a way to restore the deleted attributes?

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    You seem to have missed the data use model fundamentals used by most GIS software -- Data does not exist in the map project, just the drawing rules. So yes, if you alter a shared data source in one project, it's altered in both. The probability of restoration is outside our ability to judge -- it depends on where you got the data, and how you saved it. – Vince Jun 25 '17 at 19:11
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Short: Yes, you lost the records or attributes by deleting them.

QGIS project files - in general - only store references to data (in files, databases or from services). The same is true for most other GIS!

You need to duplicate the data files before deleting to keep a backup. If you don't have a backup, you're probably out of luck.

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  • I also duplicated the data in the project (right click on the shape file > duplicate), but then again, the changes I made in the duplicated shape file were also deleted in the original shape file... I don't understand it... Very dangerous for 'newbies' :-( – Boswachter_Marc Jun 25 '17 at 19:16
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    Duplicating a layer in a GIS does not create a copy of the data. There are just two references to the same data source. – underdark Jun 25 '17 at 19:17
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    'Save As' and give it a new name, rather than duplicate, to make a completely separate copy of your data. – Martin Hügi Jun 25 '17 at 19:38
  • Thanks Martin, I will keep it in mind for the next 'learning' project ;-) – Boswachter_Marc Jun 25 '17 at 19:59

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