Re: Syntax error needs fresh eyeballs

Rich Shepard <rshepard(at)appl-ecosys(dot)com> writes:
> My schema includes three tables and psql throws an error I'm not seeing
> when I try to read the schema into the database. I'd appreciate fresh eyes
> looking at the table and learning what error I'm not seeing.

Hm, seems straightforward enough to me: the only uniqueness constraint
you've got in Weather_Params is

> PRIMARY KEY (site_id, param)

but in Weather_Data you write

> param TEXT
> REFERENCES Weather_Params(param),

so you get this

> ERROR: there is no unique constraint matching given keys for referenced
> table "weather_params".

because Weather_Params.param isn't constrained to be unique.
Weather_Params' pkey constrains the combination of site_id and param to be
unique, but that doesn't make param alone unique, so param in Weather_Data
isn't enough to reference a well-defined row of Weather_Params.

Seeing that Weather_Data also has a site_id column, I'm going to guess
that what you wanted to put in Weather_Data is a two-column FK:

FOREIGN KEY (site_id, param) REFERENCES Weather_Params (site_id, param)

That would match Weather_Params' pkey, so it's enough to identify a
unique row of Weather_Params.

regards, tom lane