You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@impala.apache.org by ar...@apache.org on 2018/07/25 19:28:17 UTC
[06/10] impala git commit: IMPALA-7218: [DOCS] Support column list in
ALTER VIEW
IMPALA-7218: [DOCS] Support column list in ALTER VIEW
Change-Id: I19e5cf97302a46738fd832344415fb7ad4ca0e41
Reviewed-on: http://gerrit.cloudera.org:8080/11043
Reviewed-by: Fredy Wijaya <fw...@cloudera.com>
Tested-by: Impala Public Jenkins <im...@cloudera.com>
Project: http://git-wip-us.apache.org/repos/asf/impala/repo
Commit: http://git-wip-us.apache.org/repos/asf/impala/commit/def5c881
Tree: http://git-wip-us.apache.org/repos/asf/impala/tree/def5c881
Diff: http://git-wip-us.apache.org/repos/asf/impala/diff/def5c881
Branch: refs/heads/master
Commit: def5c881b1dee93848daea52d93a0602e11338ca
Parents: 73be154
Author: Alex Rodoni <ar...@cloudera.com>
Authored: Tue Jul 24 17:22:32 2018 -0700
Committer: Alex Rodoni <ar...@cloudera.com>
Committed: Wed Jul 25 19:19:16 2018 +0000
----------------------------------------------------------------------
docs/topics/impala_alter_view.xml | 87 ++++++++++++++++++++--------------
1 file changed, 52 insertions(+), 35 deletions(-)
----------------------------------------------------------------------
http://git-wip-us.apache.org/repos/asf/impala/blob/def5c881/docs/topics/impala_alter_view.xml
----------------------------------------------------------------------
diff --git a/docs/topics/impala_alter_view.xml b/docs/topics/impala_alter_view.xml
index e0d21d9..08d26bb 100644
--- a/docs/topics/impala_alter_view.xml
+++ b/docs/topics/impala_alter_view.xml
@@ -21,7 +21,13 @@ under the License.
<concept rev="1.1" id="alter_view">
<title>ALTER VIEW Statement</title>
- <titlealts audience="PDF"><navtitle>ALTER VIEW</navtitle></titlealts>
+
+ <titlealts audience="PDF">
+
+ <navtitle>ALTER VIEW</navtitle>
+
+ </titlealts>
+
<prolog>
<metadata>
<data name="Category" value="Impala"/>
@@ -38,67 +44,78 @@ under the License.
<conbody>
<p>
- <indexterm audience="hidden">ALTER VIEW statement</indexterm>
- Changes the characteristics of a view. The syntax has two forms:
+ The <codeph>ALTER VIEW</codeph> statement changes the characteristics of a view.
</p>
- <ul>
- <li>
- The <codeph>AS</codeph> clause associates the view with a different query.
- </li>
- <li>
- The <codeph>RENAME TO</codeph> clause changes the name of the view, moves the view to
- a different database, or both.
- </li>
- </ul>
-
<p>
- Because a view is purely a logical construct (an alias for a query) with no physical data behind it,
- <codeph>ALTER VIEW</codeph> only involves changes to metadata in the metastore database, not any data files
- in HDFS.
+ Because a view is a logical construct, an alias for a query, with no physical data behind
+ it, <codeph>ALTER VIEW</codeph> only involves changes to metadata in the metastore
+ database, not any data files in HDFS.
</p>
-<!-- View _permissions_ don't rely on underlying table. -->
+ <p>
+ To see the definition of the updated view, issue a <codeph>DESCRIBE FORMATTED</codeph>
+ statement.
+ </p>
-<!-- Could use views to grant access only to certain columns. -->
+ <p conref="../shared/impala_common.xml#common/syntax_blurb"/>
-<!-- Treated like a table for authorization. -->
+<codeblock>ALTER VIEW [<varname>database_name</varname>.]<varname>view_name</varname>
+ [(<varname>column_name</varname> [COMMENT '<varname>column_comment</varname>'][, ...])]
+ AS <varname>select_statement</varname>;
-<!-- ALTER VIEW that queries another view - possibly a runtime error. -->
+ALTER VIEW [<varname>database_name</varname>.]<varname>view_name</varname>
+ RENAME TO [<varname>database_name</varname>.]<varname>view_name</varname>;</codeblock>
- <p conref="../shared/impala_common.xml#common/syntax_blurb"/>
+ <ul>
+ <li>
+ The <codeph>AS</codeph> clause associates the view with a different query.
+ <p>
+ An optional list of column names can be specified with or without the column-level
+ comments.
+ </p>
+
+ <p>
+ For example:
+<codeblock>
+ALTER VIEW v1 AS SELECT x, UPPER(s) s FROM t2;
+ALTER VIEW v1 (c1, c2, c3) AS SELECT x, UPPER(s) s FROM t2;
+ALTER VIEW v7 (c1 COMMENT 'Comment for c1', c2) AS SELECT t1.c1, t1.c2 FROM t1;
+</codeblock>
+ </p>
+ </li>
-<codeblock>ALTER VIEW [<varname>database_name</varname>.]<varname>view_name</varname> AS <varname>select_statement</varname>
-ALTER VIEW [<varname>database_name</varname>.]<varname>view_name</varname> RENAME TO [<varname>database_name</varname>.]<varname>view_name</varname></codeblock>
+ <li>
+ The <codeph>RENAME TO</codeph> clause changes the name of the view, moves the view to a
+ different database, or both.
+ <p>
+ For example:
+<codeblock>ALTER VIEW db1.v1 RENAME TO db2.v2; -- Move the view to a different database with a new name.
+ALTER VIEW db1.v1 RENAME TO db1.v2; -- Rename the view in the same database.
+ALTER VIEW db1.v1 RENAME TO db2.v1; -- Move the view to a difference database with the same view name.</codeblock>
+ </p>
+ </li>
+ </ul>
<p conref="../shared/impala_common.xml#common/ddl_blurb"/>
<p conref="../shared/impala_common.xml#common/sync_ddl_blurb"/>
<p conref="../shared/impala_common.xml#common/security_blurb"/>
+
<p conref="../shared/impala_common.xml#common/redaction_yes"/>
<p conref="../shared/impala_common.xml#common/cancel_blurb_no"/>
<p conref="../shared/impala_common.xml#common/permissions_blurb_no"/>
- <p conref="../shared/impala_common.xml#common/example_blurb"/>
-
-<codeblock>create table t1 (x int, y int, s string);
-create table t2 like t1;
-create view v1 as select * from t1;
-alter view v1 as select * from t2;
-alter view v1 as select x, upper(s) s from t2;</codeblock>
-
-<!-- Repeat the same blurb + example to see the definition of a view, as in CREATE VIEW. -->
-
- <p conref="../shared/impala_common.xml#common/describe_formatted_view"/>
-
<p conref="../shared/impala_common.xml#common/related_info"/>
<p>
<xref href="impala_views.xml#views"/>, <xref href="impala_create_view.xml#create_view"/>,
<xref href="impala_drop_view.xml#drop_view"/>
</p>
+
</conbody>
+
</concept>