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From "Vuk Ercegovac (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-1608) [Hbase Shell] Relational Algrebra Operators
Date Sat, 27 Oct 2007 00:17:51 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-1608?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12538151
] 

Vuk Ercegovac commented on HADOOP-1608:
---------------------------------------

Hi Edward,

Is there a reason that GroupingFilterMap and IdentityFilterMap do not inherit from GroupingTableMap
and IdentityTableMap instead of directly from TableMap? There seems to be some redundant code
in the current patch. Alternatively, it may be better simply to enhance GroupingTableMap and
IdentityTableMap with filtering.

> [Hbase Shell] Relational Algrebra Operators
> -------------------------------------------
>
>                 Key: HADOOP-1608
>                 URL: https://issues.apache.org/jira/browse/HADOOP-1608
>             Project: Hadoop
>          Issue Type: Improvement
>          Components: contrib/hbase
>    Affects Versions: 0.14.1
>         Environment: All environments 
>            Reporter: Edward Yoon
>            Priority: Minor
>             Fix For: 0.16.0
>
>         Attachments: patch_v01.txt, patch_v02.txt, patch_v03.txt, patch_v04.txt, patch_v05.txt,
patch_v06.txt, patch_v07.txt, patch_v08.txt, patch_v09.txt, patch_v10.txt, patch_v11.txt,
patch_v12.txt, patch_v13.txt
>
>
> Development of relational algebra operators has begun.
>  * Projection 
>   ** selects a subset of the columnfamilies of a relation  
>   ** Result = π ~column_list~ (Relation) 
> {code}
> Hbase > Result = Relation.Projection('year','legnth');
> Hbase > save Result into table('result');
> {code}
>  * Selection
>   ** See : HADOOP-2003 issue's description
> {code}
> Hbase > Result = Relation.Selection(length > 100 and studioName = 'Fox'); 
> Hbase > save Result into table('result');
> {code}
>  * Group
>   ** more details about 'GROUP' operation will be handled in HADOOP-1658 issue. 
>  * θ Join
>  ** The join of two relations R1(A ~1~,A ~2~,...,A ~n~) and R2(B ~1~,B ~2~,...,B ~m~)
is a relation with degree k=n+m and attributes (A ~1~,A ~2~,...,A ~n~, B ~1~,B ~2~,...,B ~m~)
that satisfy the join condition
> {code}
> Hbase > R1 = table('movieLog_table');
> Hbase > R2 = table('personInfo_table');
> Hbase > Result = R1.join(R1.producer: = R2.ROW) and R2; 
>      or Result = R1.join(R1.actor:hero = R2.Row) and R2;
>      or Result = R1.join(R1.actor:hero = R2.Row and R1.studioName = 'Fox' and R2.occupation
= 'singer');
> {code}

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