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From "Tyler Hobbs (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-7970) JSON support for CQL
Date Tue, 03 Feb 2015 22:25:38 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-7970?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14304148#comment-14304148
] 

Tyler Hobbs commented on CASSANDRA-7970:
----------------------------------------

bq. But I can imagine situations where some values are collected via JSON and "enriched" by
the application code \[...\]

That's a fair point.  If users ask for it, I would probably be okay adding it, but let's take
the "wait and see" approach for now.

> JSON support for CQL
> --------------------
>
>                 Key: CASSANDRA-7970
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7970
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: API
>            Reporter: Jonathan Ellis
>            Assignee: Tyler Hobbs
>             Fix For: 3.0
>
>         Attachments: 7970-trunk-v1.txt
>
>
> JSON is popular enough that not supporting it is becoming a competitive weakness.  We
can add JSON support in a way that is compatible with our performance goals by *mapping* JSON
to an existing schema: one JSON documents maps to one CQL row.
> Thus, it is NOT a goal to support schemaless documents, which is a misfeature [1] [2]
[3].  Rather, it is to allow a convenient way to easily turn a JSON document from a service
or a user into a CQL row, with all the validation that entails.
> Since we are not looking to support schemaless documents, we will not be adding a JSON
data type (CASSANDRA-6833) a la postgresql.  Rather, we will map the JSON to UDT, collections,
and primitive CQL types.
> Here's how this might look:
> {code}
> CREATE TYPE address (
>   street text,
>   city text,
>   zip_code int,
>   phones set<text>
> );
> CREATE TABLE users (
>   id uuid PRIMARY KEY,
>   name text,
>   addresses map<text, address>
> );
> INSERT INTO users JSON
> {‘id’: 4b856557-7153,
>    ‘name’: ‘jbellis’,
>    ‘address’: {“home”: {“street”: “123 Cassandra Dr”,
>                         “city”: “Austin”,
>                         “zip_code”: 78747,
>                         “phones”: [2101234567]}}};
> SELECT JSON id, address FROM users;
> {code}
> (We would also want to_json and from_json functions to allow mapping a single column's
worth of data.  These would not require extra syntax.)
> [1] http://rustyrazorblade.com/2014/07/the-myth-of-schema-less/
> [2] https://blog.compose.io/schema-less-is-usually-a-lie/
> [3] http://dl.acm.org/citation.cfm?id=2481247



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