Mapping JSON in Hive where Nested Fields Have Underscores - json

Question

We are attempting to create a schema to load a massive JSON structure into Hive. We are having a problem, however, in that some fields have leading underscores for names--at the root level, this is fine, but we have not found a way to make this work for nested fields.
Sample JSON:
{
"_id" : "319FFE15FF908EDD86B7FDEADBEEFBD8D7284128841B14AA6A966923C268DF39",
"SomeThing" :
{
"_SomeField" : 22,
"AnotherField" : 2112,
"YetAnotherField": 1
}
. . . etc . . . .
Using a schema as follows:
create table testSample
(
id string,
something struct
<
somefield:int,
anotherfield:bigint,
yetanotherfield:int
>
)
row format serde 'org.openx.data.jsonserde.JsonSerDe'
with serdeproperties
(
"mapping.id" = "_id",
"mapping.somefield" = "_somefield"
);
This schema builds OK--however, after loading the in above sample, the value of "somefield" (the nested + leading underscore one) is always null (all the other values exist and are correct).
We've been trying a lot of syntax combinations, but to no avail.
Does anyone know the trick to hap a nested field with a leading underscore in its name?
Cheers!

Answer 1

Answering my own question here: there is no trick because you can't.
However, there's an easy work-around: you can tell Hive to treat the names as literals upon creating the schema. If you do this, you will also need to query using the same literal syntax. In the above example, it would look like:
`_something` struct<rest_of_definitions>
without any special serde properties for it.
Then use again in query:
select stuff.`_something` from sometable;
e.g., schema:
create table testSample
(
id string,
something struct
<
`_somefield`:int,
anotherfield:bigint,
yetanotherfield:int
>
)
row format serde 'org.openx.data.jsonserde.JsonSerDe'
with serdeproperties("mapping.id" = "_id");
for an input JSON like:
{
"_id": "someuid",
"something":
{
"_somefield": 1,
"anotherfield": 2,
"yetanotherfield": 3
}
}
with a query like:
select something.`_somefield`
from testSample
where something.anotherfield = 2;