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https://issues.apache.org/jira/browse/HADOOP-1608?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12516184
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stack commented on HADOOP-1608:
-------------------------------
Isn't 'projection' what is more commonly known in db-speak as a 'view'? How
hard would it be to implement 'projection' -- or view -- in a more sql-like
manner (see mysql page for example:
http://dev.mysql.com/doc/refman/5.0/en/create-view.html)
'selection' is too close in operation to 'select'. Why not name them the same
(and have 'select' pick up the 'selection' capabilities)?
'store' seems to be done in (non-standard) SQL as a suffix 'into' on select
statements.
In fact, how hard would it be to add all of these new capabilities in a more
sql-like fashion? Below I redo your examples:
{code}
HBase >SELECT 'year', 'length' FROM 'movieLog_table' SORT BY 'year' INTO table
'temp_table';
...
OR
HBase> CREATE VIEW year_length AS SELECT 'year', 'length' FROM 'movieLog_table'
SORT BY 'year';
HBase> SELECT year_length INTO TABLE 'temp_table';
...
HBase > SELECT 'year', 'length' FROM 'movieLog_table' SORT BY 'year' WHERE
('length' > 100) INTO table 'temp_table2';
...
HBase > SELECT 'year', 'length', 'studioName' FROM 'movieLog_table' WHERE
'length' > 100 SORT BY 'studioName' INTO FILE '/tmp/x.txt';
{code}
(There's a javacc pl/sql parser over in the javacc grammers page)
In this wiki page, http://wiki.apache.org/lucene-hadoop/Hbase/ShellPlans, when
you say 'relational operator', in what sense do you mean? (database? computer
science?). Can you add examples of how you would express matrix add,
delete,and transpositions in hbase shell? It would help figure if going too
far down the sql path would take you away from being able to add support for
these operations (though it seems like your intent is to add traditional rdbms
sql-like operations for hbase, is that right?)
Thanks Edward
> [HbaseShell] Relational Algrebra Operators
> ------------------------------------------
>
> Key: HADOOP-1608
> URL: https://issues.apache.org/jira/browse/HADOOP-1608
> Project: Hadoop
> Issue Type: Improvement
> Components: contrib/hbase
> Environment: All environments
> Reporter: edward yoon
> Priority: Minor
> Fix For: 0.14.0
>
> Attachments: shell_r_operators_v01.patch, shell_v02.patch,
> shell_v03.patch, shell_v04.patch, shell_v05.patch
>
>
> Development of relational algebra operators has begun.
> * Projection
> * Selection
> * Product
> * Rename
> * Group
> * Sort
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