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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "Hive/ViewDev" by JohnSichi
Date Mon, 11 Jan 2010 19:05:21 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.

The "Hive/ViewDev" page has been changed by JohnSichi.
http://wiki.apache.org/hadoop/Hive/ViewDev?action=diff&rev1=9&rev2=10

--------------------------------------------------

  = Use Cases =
  
- Views are a standard DBMS feature and their uses are well understood.  A typical use case
might be to create an interface layer with a consistent entity/attribute naming scheme on
top of an existing set of inconsistently named tables, without having to cause disruption
due to direct modification of the tables.  More advanced use cases would involve predefined
filters, joins, aggregations, etc for simplifying query construction by end users, as well
as sharing common definitions within ETL pipelines.
+ Views (http://issues.apache.org/jira/browse/HIVE-972) are a standard DBMS feature and their
uses are well understood.  A typical use case might be to create an interface layer with a
consistent entity/attribute naming scheme on top of an existing set of inconsistently named
tables, without having to cause disruption due to direct modification of the tables.  More
advanced use cases would involve predefined filters, joins, aggregations, etc for simplifying
query construction by end users, as well as sharing common definitions within ETL pipelines.
  
  = Scope =
  
@@ -16, +16 @@

  Beyond this, we may want to
  
   * expose metadata about view definitions and dependencies (at table-level or column-level)
in a way that makes them consumable by metadata-driven tools
+ 
+ = Syntax =
+ 
+ {{{
+ CREATE VIEW [IF NOT EXISTS] view_name [ (column_name [COMMENT column_comment], ...) ]
+ [COMMENT table_comment]
+ AS SELECT ...
+ 
+ DROP VIEW view_name
+ }}}
  
  = Implementation Sketch =
  

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