Copying between library - datatypes of columns (composite > noncomposite)

ownedbycats · Yesterday, 03:01 PM

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In my Kobo Wishlist library, #purchasecost is a composite (to calculate discount + tax on store-listed price), output's always {0:,.2f}:

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My main library, the same column is floating-point with ${0:,.2f}.

Is there a technical reason why that couldn't be copied over, or is it just to prevent idiots careless users from accidentally putting text in an integer column?

kovidgoyal · Yesterday, 08:50 PM

A composite column cant be copied to a non-composite column, they are complete different beasts under the hood. Trying to guess that the output of the composite one is compatible with the non composite one on all books basically means evaluating it on all books and checking, which, while technically do-able is too slow.

ownedbycats · Yesterday, 08:56 PM

Ah, makes sense. All the other columns I want to copy are compatible so I only need to re-insert price (& since I often buy books on sale, sometimes it differs).

Yesterday, 03:01 PM	#1
ownedbycats Custom User Title Posts: 11,566 Karma: 81412473 Join Date: Oct 2018 Location: Canada Device: Kobo Libra H2O, formerly Aura HD	Copying between library - datatypes of columns (composite > noncomposite) In my Kobo Wishlist library, #purchasecost is a composite (to calculate discount + tax on store-listed price), output's always {0:,.2f}: My main library, the same column is floating-point with ${0:,.2f}. Is there a technical reason why that couldn't be copied over, or is it just to prevent idiots careless users from accidentally putting text in an integer column?

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Yesterday, 08:50 PM	#2
kovidgoyal creator of calibre Posts: 46,004 Karma: 29579720 Join Date: Oct 2006 Location: Mumbai, India Device: Various	A composite column cant be copied to a non-composite column, they are complete different beasts under the hood. Trying to guess that the output of the composite one is compatible with the non composite one on all books basically means evaluating it on all books and checking, which, while technically do-able is too slow.

Yesterday, 08:56 PM	#3
ownedbycats Custom User Title Posts: 11,566 Karma: 81412473 Join Date: Oct 2018 Location: Canada Device: Kobo Libra H2O, formerly Aura HD	Ah, makes sense. All the other columns I want to copy are compatible so I only need to re-insert price (& since I often buy books on sale, sometimes it differs).