Question

My client has given me a list of vehicles for a project. I need to get them into a table I can use, but they’re currently in a .cvs file. I’ve read around and found some info, but nothing that solves my particular problem.

I’ve generated a model that matches the info in the .cvs file(id, year, make, model, trim), run the migration, and now have the table I need. The issue comes up when I try to use psql COPY. Here’s what I’ve read will work:

copy list_vehicles from '/path/to/list.csv' DELIMITERS ',' CSV;

but it gives me

ERROR:  missing data for column "created_at"

Fine, so I try this:

copy list_vehicles (id, year, make, model, trim)  from '/path/to/list.csv' DELIMITERS ',' CSV;

and I get back

ERROR:  null value in column "created_at" violates not-null constraint

Ok, so then this should work:

copy list_vehicles (id, year, make, model, trim)  from '/path/to/list.csv' DELIMITERS ',' WITH NULL AS ' ' CSV FORCE NOT NULL created_at;

nope,

ERROR:  FORCE NOT NULL column "created_at" not referenced by COPY

I’m not sure where to go from here. I was thinking of trying to take the created_at column back out for now, then add it in another migration? Any guidance would be much appreciated.

Thanks

Answer 1

The created_at column is made automatically by Rails most of the time when you run a migration to create a table for a new model. It’s generally populated most of the time by the Rails default code when you create a new model object in your application.

You’re loading the data directly into the database, though, bypassing all the Rails code. Which is fine, but you also need to do the things Rails does.

I think the easiest way is going to be to remove the created_at and other columns from the database directly, loading your CSV file, and then adding the columns back in.