Re^4: [OT] MySQL recalibrating a sort-index

I haven't tested it yet, but why does an UPDATE from a temp table have no conflict with the UNIQUEness of f_sort (see the UPDATE in the OP)?

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)

Wikisyntax for the Monastery}

Comment on Re^4: [OT] MySQL recalibrating a sort-index

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Re^5: [OT] MySQL recalibrating a sort-index by erix (Prior) on Feb 17, 2018 at 08:13 UTC
Ah, you were looking for a DEFERRABLE CONSTRAINT, which postpones the constraint-validation to the end of a transaction. So, you'd do (again, postgres): `create table tree ( f_node_id int primary key , f_parent_id int , f_name text , f_sort float , constraint tree_parent_sort_uniq_idx unique (f_parent_id, f_sort) d +eferrable );` [download] This lets you mess about with non-unique states for the duration of a transaction. The constraint (here: uniqueness) is only then enforced. I can't imagine MariaDB does not have this functionality but I can't find it in the documentation. (I looked for DEFERRED or DEFERRABLE. The MariaDB docs list 'DEFERRED' as a reserved word but I see no functionality associated with it.)	[reply] [d/l]
Re^6: [OT] MySQL recalibrating a sort-index by LanX (Saint) on Feb 17, 2018 at 10:03 UTC
> Ah, you were looking for a DEFERRABLE CONSTRAINT, which postpones the constraint Yeah this would be nice. > I can't imagine MariaDB does not have this functionality .... And no it doesn't. https://stackoverflow.com/questions/5014700/in-mysql-can-i-defer-referential-integrity-checks-until-commit Though REPLACE turns out to be a workaround, I'm glad that performance is no issue in my case. Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :) Wikisyntax for the Monastery}	[reply]