Hi Everybody!
I looked up this todo, and figured out a plan, how the implementation could be written.
The main challenge is to keep constraints and indexes (for unique and PK constraints) consistent.
Fortunately this is already realized in the case of an index. So at ALTER INDEX RENAME the consistency is given by an extra check in tablecmds.c (Line 2246), where a function is finally called, RenameConstraintById (pg_constraint.c Line 604).
My idea is, to do that analog for ALTER CONSTRAINT RENAME too. So renaming the constraint is going to be done in tablecmds.c as for indexes, tables, sequences, views. And after checking whether the renametype is constraint, an extra rename has to be done for the index. Getting the index can be done with the function get_constraint_index (pg_depend.c Line 475). Now it should be possible to do the same as in RenameConstraintById.
Is that so legal? Is anything else to be considered?
I appreciate any suggestion, and maybe some help too, as I'm not so familiar with the source.
Thanks in advance,
Viktor
(Student of technical unverstity of Vienna)