[
https://issues.apache.org/jira/browse/TAJO-1359?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14532848#comment-14532848
]
ASF GitHub Bot commented on TAJO-1359:
--------------------------------------
Github user jihoonson commented on a diff in the pull request:
https://github.com/apache/tajo/pull/422#discussion_r29862737
--- Diff:
tajo-plan/src/main/java/org/apache/tajo/plan/nameresolver/NameResolver.java ---
@@ -162,18 +210,22 @@ static Column
resolveFromCurrentAndChildNode(LogicalPlan.QueryBlock block, Colum
}
/**
- * It tries to find a full qualified column name from all relations in
the current block.
+ * Lookup a column among all relations in the current block from a
column name.
+ *
+ * It assumes that <code>columnName</code> is not any qualified name.
*
* @param block The current query block
- * @param columnRef The column reference to be found
+ * @param columnName The column reference to be found
* @return The found column
*/
- static Column resolveFromAllRelsInBlock(LogicalPlan.QueryBlock block,
- ColumnReferenceExpr columnRef)
throws VerifyException {
+ static Column lookupColumnFromAllRelsInBlock(LogicalPlan.QueryBlock
block,
+ String columnName) throws
VerifyException {
+
Preconditions.checkArgument(CatalogUtil.isSimpleIdentifier(columnName));
--- End diff --
It would be nice if you add an appropriate error message for pre-condition
checking failure.
> Add nested field projector and language extension to project nested record
> --------------------------------------------------------------------------
>
> Key: TAJO-1359
> URL: https://issues.apache.org/jira/browse/TAJO-1359
> Project: Tajo
> Issue Type: Sub-task
> Components: parser, physical operator, planner/optimizer
> Reporter: Hyunsik Choi
> Assignee: Hyunsik Choi
> Fix For: 0.11.0
>
> Attachments: TAJO-1359.patch, TAJO-1359_2.patch, TAJO-1359_3.patch,
> TAJO-1359_4.patch, TAJO-1359_5.patch, TAJO-1359_6.patch, TAJO-1359_7.patch
>
>
> We need to improve Projector class to get nested record fields, and we also
> add some language extension to specify certain nested records in table
> schema. Both works should be done together. Otherwise, we need to test an
> entire work process.
> Using dot '.' would be good for the syntax to specify nested fields. Many
> systems (Hive, Google BigQuery, and Drill) already use this syntax. Probably,
> many users are familiar with this form.
> For example, if *employee* is a root nested record field and it includes
> *age* and *name* fields, consisting two fields lastname and firstname, we can
> specify them individually as follows:
> {code}
> SELECT employee.age, employee.name.lastname, employee.name.firstname FROM ...
> {code}
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