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https://issues.apache.org/jira/browse/TAJO-1832?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14804778#comment-14804778
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ASF GitHub Bot commented on TAJO-1832:
--------------------------------------
Github user hyunsik commented on a diff in the pull request:
https://github.com/apache/tajo/pull/756#discussion_r39816146
--- Diff:
tajo-sql-parser/src/main/antlr4/org/apache/tajo/parser/sql/SQLParser.g4 ---
@@ -106,9 +106,9 @@ if_exists
;
create_table_statement
- : CREATE EXTERNAL TABLE (if_not_exists)? table_name table_elements
(TABLESPACE spacename=identifier)? USING storage_type=identifier
+ : CREATE EXTERNAL TABLE (if_not_exists)? table_name (table_elements)?
(TABLESPACE spacename=identifier)? USING storage_type=identifier
--- End diff --
This grammar allows to create table without parenthesis ``(..)``. It looks
good to me.
I also have another suggestion. How do you think about a special notation
with parenthesis like ``CREATE EXTERNAL TABLE (*) USING JSON``. I used asterisk
``*`` as a meaning of becoming anything and the infinite number of fields,
which can be zero to up to be infinite.
> Well support for self-describing data formats
> ---------------------------------------------
>
> Key: TAJO-1832
> URL: https://issues.apache.org/jira/browse/TAJO-1832
> Project: Tajo
> Issue Type: New Feature
> Components: Planner/Optimizer
> Reporter: Jihoon Son
> Assignee: Jihoon Son
>
> *Problem*
> Tajo already has a support for self-describing data formats like JSON,
> Parquet, or ORC. While they are capable of providing schema information by
> themselves, users must define schema to query on them with the current
> implementation. To solve this inconvenience, we have to improve our query
> planner to support self-describing data formats well.
> *Solution*
> First, we need to allow omitting schema definition for the create table
> statement. When a query is submitted for a self-describing table, the columns
> which don't exist in that table will be filled with Nulls.
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