hstore to json and back again - Mailing list pgsql-general

Hello,

I'm trying to migrate an existing hstore column to json in Postgres
9.3, and I'd like to be able to run the script in reverse. I know not
all JSON can turn back into hstore, but since this is coming from an
old hstore column, I know the structure is flat (no nesting), and that
all values are strings.

Here is the SQL I'm using to go hstore -> json:

UPDATE foo
SET datahash_new = to_json(datahash_old)
;

Is there any SQL I can use to go backwards?:
UPDATE foo
SET datahash_old = xxxxx(datahash_new)
;

I understand why there is not a general-purpose solution, but in my
case this should be possible. I've tried to cook something up with
json_each_text, but I haven't been able to figure it out. Can anyone
offer any help?

Thanks,
Paul

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