How to query PostgreSQL's json fields from Rails

Updated . Posted . Visible to the public.

PostgreSQL offers a really handy field type: json. You can store any JSON there, in any structure.

While its flexibility is great, there is no syntactic sugar in Rails yet. Thus, you need to manually query the database.

Demo

# Given a Task model with 'details' json column
Task.where("details->>'key' = ?", "value") # matches where 'details' contains "key":"value"
Task.where("details->>'{a,b}' = ?", "value") # matches where 'details' contains "a":{"b":"value"}
Task.where("details->'a'->>'b' = ?", "value") # same as above, but via operator chaining

-> returns JSON, whereas ->> returns text. Note that the key(s) must be passed with single quotes.

Updating records is not supported for json columns Show archive.org snapshot . jsonb columns can be updated, but that needs a different syntax.

Dominik Schöler
Last edit
Deleted user #5298
Keywords
array, pg, psql, read
License
Source code in this card is licensed under the MIT License.
Posted by Dominik Schöler to makandra dev (2016-01-11 14:25)