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https://issues.apache.org/jira/browse/TAJO-1832?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14902051#comment-14902051
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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_r40056411
  
    --- Diff: 
tajo-core-tests/src/test/java/org/apache/tajo/engine/query/TestQueryOnSelfDescTable.java
 ---
    @@ -0,0 +1,185 @@
    +/**
    + * Licensed to the Apache Software Foundation (ASF) under one
    + * or more contributor license agreements.  See the NOTICE file
    + * distributed with this work for additional information
    + * regarding copyright ownership.  The ASF licenses this file
    + * to you under the Apache License, Version 2.0 (the
    + * "License"); you may not use this file except in compliance
    + * with the License.  You may obtain a copy of the License at
    + *
    + *     http://www.apache.org/licenses/LICENSE-2.0
    + *
    + * Unless required by applicable law or agreed to in writing, software
    + * distributed under the License is distributed on an "AS IS" BASIS,
    + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    + * See the License for the specific language governing permissions and
    + * limitations under the License.
    + */
    +
    +package org.apache.tajo.engine.query;
    +
    +import org.apache.tajo.QueryTestCaseBase;
    +import org.apache.tajo.exception.AmbiguousColumnException;
    +import org.apache.tajo.exception.TajoException;
    +import org.junit.After;
    +import org.junit.Test;
    +
    +import java.io.IOException;
    +import java.sql.ResultSet;
    --- End diff --
    
    Unused import


> 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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