swift - CoreData: Not null property should be optional? -

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i'm not sure best practice of swift , coredata. think not null property should optional basically?

for example 

import foundation import coredata  class item: nsmanagedobject {     @nsmanaged var itemid: string // not null property     @nsmanaged var itemprice: string? // null possible }

i wonder should notify other programmers property not-null or not.

i know do usually. question sound opinion-based i'm sure how dealing optional helpful others.

fyi found similar question

coredata - setting property of entity not null - should attribute set optional or mandatory

from https://developer.apple.com/library/mac/documentation/cocoa/conceptual/coredata/articles/cdmom.html#//apple_ref/doc/uid/tp40002328-sw6 .. mentioned - can specify attribute optional—that is, not required have value. in general, however, discouraged doing so—especially numeric values (typically can better results using mandatory attribute default value—in model—of 0)


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