MySQL delete multiple rows in one query conditions unique to each row
You were very close, you can use this: Please see this fiddle.
unique-constraint
postgresql: error duplicate key value violates unique constraint
As the error message tells you – you can not have two rows with the same value in the columns dementia_type, snapid since they need to be unique. You have to make sure that the two databases has the same values for dementia_type, snapid. A workaround would be to add a column to your table alter table t_types_of_dementia add … Read more
ERROR: there is no unique constraint matching given keys for referenced table “bar”
It’s because the name column on the bar table does not have the UNIQUE constraint. So imagine you have 2 rows on the bar table that contain the name ‘ams’ and you insert a row on baz with ‘ams’ on bar_fk, which row on bar would it be referring since there are two rows matching?