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8377b9949c
For this change to land in master, the audience="hidden" code review needs to be completed first. Otherwise, the doc build would still work but the audience="hidden" content would be visible rather than hidden as desired. Some work happening in parallel might introduce additional instances of audience="Cloudera". I suggest addressing those in a followup CR so this global change can land quickly. Since the changes apply across so many different files, but are so narrow in scope, I suggest that the way to validate (check that no extraneous changes were introduced accidentally) is to diff just the changed lines: git diff -U0 HEAD^ HEAD In patch set 2, I updated other topics marked audience="Cloudera" by CRs that were pushed in the meantime. Change-Id: Ic93d89da77e1f51bbf548a522d98d0c4e2fb31c8 Reviewed-on: http://gerrit.cloudera.org:8080/5613 Reviewed-by: John Russell <jrussell@cloudera.com> Tested-by: Impala Public Jenkins
105 lines
3.8 KiB
XML
105 lines
3.8 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!--
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Licensed to the Apache Software Foundation (ASF) under one
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or more contributor license agreements. See the NOTICE file
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distributed with this work for additional information
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regarding copyright ownership. The ASF licenses this file
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to you under the Apache License, Version 2.0 (the
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"License"); you may not use this file except in compliance
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with the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing,
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software distributed under the License is distributed on an
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"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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KIND, either express or implied. See the License for the
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specific language governing permissions and limitations
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under the License.
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-->
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<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
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<concept rev="1.1" id="alter_view">
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<title>ALTER VIEW Statement</title>
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<titlealts audience="PDF"><navtitle>ALTER VIEW</navtitle></titlealts>
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<prolog>
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<metadata>
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<data name="Category" value="Impala"/>
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<data name="Category" value="SQL"/>
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<data name="Category" value="DDL"/>
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<data name="Category" value="Tables"/>
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<data name="Category" value="Schemas"/>
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<data name="Category" value="Views"/>
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<data name="Category" value="Developers"/>
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<data name="Category" value="Data Analysts"/>
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</metadata>
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</prolog>
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<conbody>
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<p>
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<indexterm audience="hidden">ALTER VIEW statement</indexterm>
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Changes the characteristics of a view. The syntax has two forms:
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</p>
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<ul>
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<li>
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The <codeph>AS</codeph> clause associates the view with a different query.
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</li>
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<li>
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The <codeph>RENAME TO</codeph> clause changes the name of the view, moves the view to
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a different database, or both.
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</li>
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</ul>
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<p>
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Because a view is purely a logical construct (an alias for a query) with no physical data behind it,
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<codeph>ALTER VIEW</codeph> only involves changes to metadata in the metastore database, not any data files
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in HDFS.
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</p>
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<!-- View _permissions_ don't rely on underlying table. -->
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<!-- Could use views to grant access only to certain columns. -->
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<!-- Treated like a table for authorization. -->
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<!-- ALTER VIEW that queries another view - possibly a runtime error. -->
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<p conref="../shared/impala_common.xml#common/syntax_blurb"/>
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<codeblock>ALTER VIEW [<varname>database_name</varname>.]<varname>view_name</varname> AS <varname>select_statement</varname>
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ALTER VIEW [<varname>database_name</varname>.]<varname>view_name</varname> RENAME TO [<varname>database_name</varname>.]<varname>view_name</varname></codeblock>
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<p conref="../shared/impala_common.xml#common/ddl_blurb"/>
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<p conref="../shared/impala_common.xml#common/sync_ddl_blurb"/>
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<p conref="../shared/impala_common.xml#common/security_blurb"/>
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<p conref="../shared/impala_common.xml#common/redaction_yes"/>
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<p conref="../shared/impala_common.xml#common/cancel_blurb_no"/>
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<p conref="../shared/impala_common.xml#common/permissions_blurb_no"/>
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<p conref="../shared/impala_common.xml#common/example_blurb"/>
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<codeblock>create table t1 (x int, y int, s string);
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create table t2 like t1;
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create view v1 as select * from t1;
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alter view v1 as select * from t2;
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alter view v1 as select x, upper(s) s from t2;</codeblock>
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<!-- Repeat the same blurb + example to see the definition of a view, as in CREATE VIEW. -->
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<p conref="../shared/impala_common.xml#common/describe_formatted_view"/>
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<p conref="../shared/impala_common.xml#common/related_info"/>
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<p>
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<xref href="impala_views.xml#views"/>, <xref href="impala_create_view.xml#create_view"/>,
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<xref href="impala_drop_view.xml#drop_view"/>
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</p>
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</conbody>
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</concept>
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