On Wednesday, May 27, 2015, digoal zhou <digoal.z...@gmail.com> wrote: > > 2015-05-28 1:41 GMT+08:00 David G. Johnston <david.g.johns...@gmail.com > <javascript:_e(%7B%7D,'cvml','david.g.johns...@gmail.com');>>: > >> On Tue, May 26, 2015 at 7:03 PM, digoal zhou <digoal.z...@gmail.com >> <javascript:_e(%7B%7D,'cvml','digoal.z...@gmail.com');>> wrote: >> >>> When we create table, some column use foreign key references. >>> Now PostgreSQL don't create index for the FK, and there is no problem. >>> But when some body need the index to speed up the query within these >>> APP, they need to add the index manual one-by-one when has many tables. >>> If we can add syntax for auto create index for FK by user's choose, and >>> default not create? >>> >> >> I presume you mean to modify the CREATE TABLE statement. >> >> How does this help solve the problem "when some body need the index to >> speed up the query"? >> > Sometimes, when user need delete FK's parent table's tuple, FK has an > index will improve the performance. > or sometime, user need query FK table with FK's condition (assume it need > the btree index). >
I understand why one would want a FK but if they actually thought they would need it they would have issued a create index at the same time (well, just after) they create the table. Seeing a poorly performing query and going, "crap, I forgot the index" isn't solved by this though it may make the need more obvious while the user is writing the create table in the first place. > There is no other database product do the thing, but if PG has the > syntax(when add FK, user can choose whether or not create index), users > will happy to use it. > Are you asking if such a featured would be accepted or pleading for someone to code it? David J.
