Hi Scott,
it's the latter I need; simply the ability to pass meta-data with my schema, so
the user property is just what I need.
Thanks for your help!
Andrew
>________________________________
>From: Scott Carey <scottca...@apache.org>
>To: "user@avro.apache.org" <user@avro.apache.org>; Andrew Kenworthy
><adwkenwor...@yahoo.com>
>Sent: Monday, November 14, 2011 9:09 PM
>Subject: Re: Exposing a constant in an Avro Schema
>
>
>Named types (records, fields, fixed, enum) can store arbitrary user properties
>attached to the schema ( similar to "doc" but no special meaning).
>
>
>Do you want this constant to be in every instance of your data object? If so,
>the enum is one way to do it.
>If you simply want to push metadata along with the schema, use the schema
>properties, they are name-value pairs. For example you can have "myVersion"
>attached to your schema for a record:
>
>
>{"type":"record", "name":"bar.baz.FooRecord", "myVersion":"1.1", "fields": {
> {"name":"field1", "type":"int"},
> …
> }
>}
>
>On 11/14/11 8:03 AM, "Andrew Kenworthy" <adwkenwor...@yahoo.com> wrote:
>
>
>Hi,
>>
>>
>>I would like to "embed" a schema version number in the schema that I use for
>>writing data: it would be read-only so that I can determine later on which
>>version of my avro schema was used. The best I could come up with is to
>>(ab)use an enum with a single value like this, as I couldn't find any way to
>>define a constant:
>>
>>
>>{"type":"enum","name":"version_1_1","doc":"enum indicating avro write schema
>>version 1.1","symbols":["VERSION_1_1"]}
>>
>>
>>Is there a better way to register a constant value that has no meaning within
>>the avro data file, other than to expose some kind of meta information?
>>
>>
>>Thanks,
>>
>>
>>Andrew Kenworthy
>>
>>
>
>
