Re: Fix optimization of foreign-key on update actions

Andrew Gierth wrote:
> SQL2016, 15.17 Execution of referential actions
> 
> 10) If a non-null value of a referenced column RC in the referenced
>     table is updated to a value that is distinct from the current value
>     of RC, then,
> 
>       [snip all the stuff about how ON UPDATE actions work]
> 
> does that "is distinct from" mean that IS DISTINCT FROM would be true,
> or does it mean "is in some way distinguishable from"? Nothing I can see
> in the spec suggests the latter.

My 2003 standard defines, and even condescends to be informal:

3.1.6.8 distinct (of a pair of comparable values): Capable of being distinguished within a given context.
Informally, not equal, not both null. A null value and a non-null value are distinct.

Yours,
Laurenz Albe