Re: UPDATE ... ON CONFLICT DO NOTHING

[Alexander Farber <alexander.farber@xxxxxxxxx>]

Hi Adrian -

On Tue, Mar 14, 2017 at 7:18 PM, Adrian Klaver <adrian.klaver@xxxxxxxxxxx> wrote:

On 03/14/2017 09:00 AM, Alexander Farber wrote:

My initial idea has been not to use ON CONFLICT at all, but instead only
UPDATE the words_reviews records (set "uid" or "author" to out_uid) for
which NO EXISTS already such a record with PK (uid, author)... and then

I am afraid the logic is escaping me. If the record does not exist how can you UPDATE it?

here the table with reviews of users "uid" done by users "author":

CREATE TABLE words_reviews (
        uid integer NOT NULL CHECK (uid <> author) REFERENCES words_users ON DELETE CASCADE,
        author integer NOT NULL REFERENCES words_users(uid) ON DELETE CASCADE,
        nice integer NOT NULL CHECK (nice = 0 OR nice = 1),
        review varchar(255),
        updated timestamptz NOT NULL,
        PRIMARY KEY(uid, author)

);

Since I am merging user ids (from several to one), I need to change the records in the above table too.

I need to update the PK by changing either "uid" or "author".

But this might give me conflicts, because there might be such a PK already...

Regards

Alex