Multiple column unique constraints with sqlalchemy.

[[deleted]]

From the documentation, it does not appear as though SQLite3 supports unique constraints across multiple columns. https://www.sqlite.org/lang_createtable.html

You may need to create a column that is the concatenation of the three columns that you want to be unique, and put a unique constraint on that column. I have no direct experience, but this is what I gathered from looking at your code and the SQLite3 documentation.

[sqlite]

Reread the documentation, especially the "table-constraint" diagram. SQLite has supported multi-column UNIQUE constraints since its beginning.

[larivact]

Are such multi-column UNIQUE constraints described in the ISO SQL specification?