hadoop-common-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "Hive/LanguageManual/DDL" by JohnSichi
Date Thu, 21 Jan 2010 01:09:30 GMT
Dear Wiki user,

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

The "Hive/LanguageManual/DDL" page has been changed by JohnSichi.
http://wiki.apache.org/hadoop/Hive/LanguageManual/DDL?action=diff&rev1=45&rev2=46

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

  
  A view's schema is frozen at the time the view is created; subsequent changes to underlying
tables (e.g. adding a column) will not be reflected in the view's schema.  If an underlying
table is dropped or changed in an incompatible fashion, subsequent attempts to query the invalid
view will fail.
  
+ Views are read-only and may not be used as the target of LOAD/INSERT/ALTER.
+ 
  A view may contain ORDER BY and LIMIT clauses.  If a referencing query also contains these
clauses, the query-level clauses are evaluated '''after''' the view clauses (and after any
other operations in the query).  For example, if a view specifies LIMIT 5, and a referencing
query is executed as (select * from v LIMIT 10), then at most 5 rows will be returned.
  
  Example of view creation:

Mime
View raw message