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Documentation: What about unique constraints?

See original GitHub issue

I am trying to understand what happens during copy_from if a table already contains data and a unique constraint is triggered.

By using drop_constraints=False, if a value-to-be-saved already exists in the database will it be ignored or will an error be raised?

Searching the Postgresql-9.5+ docs, I found the ON CONFLICT clause which caters for this issue.

Issue Analytics

State:
Created 5 years ago
Reactions:1
Comments:9 (5 by maintainers)

Top GitHub Comments

2reactions

palewirecommented, Apr 11, 2018

This is a good question. I do not know the answer. Shall we write a unit test?

1reaction

igncampacommented, Apr 13, 2018

Yeah in my opinion the default behavior should always be to raise the IntegrityError but allow users to pass in an ON CONFLICT DO NOTHING argument since the latter might have unintended consequences (such a silently omitting rows).

Sounds reasonable to me.

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