On 11.02.25 14:36, Álvaro Herrera wrote:
On 2025-Feb-10, Isaac Morland wrote:
I'm having a lot of trouble understanding the operational distinction
between your 'u' and 'U'. If it's not enforced, it cannot be assumed to be
valid, regardless of whether it was valid in the past. I'm not sure what I
think of a single character vs. 2 booleans, but there are only 3 sensible
states either way: valid enforced, invalid enforced, and invalid unenforced.
I kinda agree with you and would prefer that things were that way as
well. But look at the discussion starting at
https://postgr.es/m/CAExHW5tV23Sw+Nznv0KpdNg_t7LrXY1WM9atiC=ekksskhs...@mail.gmail.com
whereby it was apparently established that if you have a
NOT VALID NOT ENFORCED
constraint, and you make it enforced, then you should somehow end up
with a NOT VALID ENFORCED constraint, which says to me that we need to
store the fact that the constraint was NOT VALID to start with; and
correspondingly if it's VALID NOT ENFORCED and you enforce it, then it
ends up VALID ENFORCED. If we take this view of the world (with which,
I repeat, I disagree) then we must keep track of whether the constraint
was valid or not valid to start with. And this means that we need to
keep convalidated=true _regardless_ of whether conenforced is false.
So in this view of the world there aren't three states but four.
I would prefer there to be three states as well, but apparently I'm
outvoted on this.
Just to make this a bit more confusing, here is another interpretation
of the state NOT ENFORCED VALID (they call it DISABLE VALIDATE):
https://docs.oracle.com/en/database/oracle/oracle-database/19/sqlrf/constraint.html#GUID-1055EA97-BA6F-4764-A15F-1024FD5B6DFE__I1002349
"""
DISABLE VALIDATE disables the constraint and drops the index on the
constraint, but keeps the constraint valid. This feature is most useful
in data warehousing situations, because it lets you load large amounts
of data while also saving space by not having an index. This setting
lets you load data from a nonpartitioned table into a partitioned table
using the exchange_partition_subpart clause of the ALTER TABLE statement
or using SQL*Loader. All other modifications to the table (inserts,
updates, and deletes) by other SQL statements are disallowed.
"""
