Re: Duplicate JSON Object Keys

On 03/07/2013 02:48 PM, David E. Wheeler wrote:
> This behavior surprised me a bit:
>
> david=# select '{"foo": 1, "foo": 2}'::json;
> json
> ----------------------
> {"foo": 1, "foo": 2}
>
> I had expected something more like this:
>
> david=# select '{"foo": 1, "foo": 2}'::json;
> json
> ------------
> {"foo": 2}
>
> This hasn’t been much of an issue before, but with Andrew’s JSON enhancements going in, it will start to cause problems:
>
> david=# select json_get('{"foo": 1, "foo": 2}', 'foo');
> ERROR: field name is not unique in json object
>
> Andrew tells me that the spec requires this. I think that’s fine, but I would rather that it never got to there.

Specifically, rfc4627 says (note last sentence):

2.2. Objects

An object structure is represented as a pair of curly brackets
surrounding zero or more name/value pairs (or members). A name is a
string. A single colon comes after each name, separating the name
from the value. A single comma separates a value from a following
name. The names within an object SHOULD be unique.

cheers

andrew