A word of caution on the union type. You may find support for unions very
patchy if you are hoping to process records using well known data
processing engines. We’ve been unable to usefully read union types in both
Apache Spark and Hive for example. The simple null union construct is the
exception: [null, typeA], as it is usually represented by a nullable
columns of typeA. We’ve resorted to prohibiting schemas with complex unions
so that our producers can’t create data that is not fully readable by our
consumers.
Elliot.
On Fri, 25 May 2018 at 22:30, Motoko Kusanagi <
major-motoko-kusan...@outlook.com> wrote:
> Hi Michael,
>
> Thanks!! Yes, it does.
>
> Scott
> ------------------------------
> *From:* Michael Smith <micha...@syapse.com>
> *Sent:* Friday, May 25, 2018 2:21 PM
> *To:* user@avro.apache.org
> *Subject:* Re: Avro Schema Question
>
> {"type": "int"}, {"type": "string"} is not valid json, so you definitely
> can't do that. But
>
> [{"type": "int"}, {"type": "string"}] is a valid schema -- it can encode a
> single value that is either an int or a string. At the highest level, your
> schema can only be one type, but that type may be (and in fact probably
> will be) a complex type -- a union of records or a single record.
>
> Does that answer your question?
>
> On Fri, May 25, 2018 at 5:08 PM Motoko Kusanagi <
> major-motoko-kusan...@outlook.com> wrote:
>
> Hi,
>
>
> I read the specification multiple times. In the specification, it says "A
> Schema is represented in JSON <http://www.json.org/> by one of:" in the
> Schema Declaration section. The "one" confuses me as I am interpreting it
> as exactly one of the 3 that it listed.
>
>
> In short, can I do this as a single schema?
>
> {type : int},
>
> {type : string},
>
> {type : int},
>
>
> Or do the following as a single schema?
>
> {type : int},
>
> {type : record ....},
>
> {type : record ....}, // Not the same as the previous.
>
> {type : string},
>
>
> Or do I have to "embed" the above under a complex type like a record if I
> want complex schema? Or does "one of" mean I have to choose one and exactly
> one for the high top-most level of the schema?
>
>
> Thanks!!
>
>
>
> --
>
> Michael A. Smith — Senior Systems Engineer
> ------------------------------
>
> micha...@syapse.com
> syapse.com
> <http://www.syapse.com/>100 Matsonford Road
> <https://maps.google.com/?q=100+Matsonford+Rd&entry=gmail&source=g>
> Five Radnor Corporate Center
> Suite 444
> Radnor, PA 19087
> https://www.linkedin.com/in/michaelalexandersmith
>
>
