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https://issues.apache.org/jira/browse/TAJO-809?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Hyunsik Choi reassigned TAJO-809:
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Assignee: Hyunsik Choi (was: David Chen)
> Language extension for non-scalar types
> ---------------------------------------
>
> Key: TAJO-809
> URL: https://issues.apache.org/jira/browse/TAJO-809
> Project: Tajo
> Issue Type: New Feature
> Reporter: David Chen
> Assignee: Hyunsik Choi
>
> This ticket is to track the work for defining the syntax for nested schemas,
> maps, arrays, and unions and the work for adding the syntax to the parser.
> Initially, we can add stubs for the parser endpoints that will then be
> fleshed out when support for the data type is actually implemented (see other
> subtasks of TAJO-710).
> I have an idea of a possible DDL syntax for these types, and I would like to
> get your feedback on it. I considered just using Hive's syntax but I felt
> that it was not the best syntax for these types.
> Instead of calling nested records "structs" like the way Hive does, I simply
> call them records as well and use the same syntax used for declaring the
> top-level record fields:
> {code}
> create table record_example (
> nested_field record (
> field1 int,
> field2 double),
> two_levels_nested record (
> inner_nested record (
> field3 string,
> field4 int),
> field5 int),
> ) using parquet;
> {code}
> For arrays, maps, and unions, I am using a syntax inspired by Scala's syntax
> for generics:
> {code}
> create table array_example (
> int_array array[int],
> record_array array[record (
> field1 int,
> field2 string)]
> ) using avro;
> create table map_example (
> string_to_int map[string, int],
> int_to_record map[int, record (
> field1 string,
> field2 int)],
> ) using avro;
> create table union_example (
> integers union[bit, smallint, integer, bigint]
> ) using parquet;
> {code}
> Of course, it is possible that when we implement these data types, we may
> make changes to the syntax, but for now, I think we should define an initial
> language. Once the initial syntax has stabilized, I will write a formal
> grammar for it.
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