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c8d21d0137
Change-Id: Ibb7ce9fa20fb1d6551d718c8ec25c746a72b40d9 Reviewed-on: http://gerrit.cloudera.org:8080/11370 Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com> Reviewed-by: Vuk Ercegovac <vercegovac@cloudera.com>
111 lines
3.3 KiB
XML
111 lines
3.3 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 id="comment">
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<title>COMMENT Statement</title>
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<titlealts audience="PDF">
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<navtitle>COMMENT</navtitle>
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</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="Hive"/>
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<data name="Category" value="Metastore"/>
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<data name="Category" value="ETL"/>
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<data name="Category" value="Ingest"/>
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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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The <codeph>COMMENT</codeph> statement adds, changes, or removes a comment about a
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database, a table, or a column.
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</p>
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<p>
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You can alternatively use the <codeph>CREATE</codeph> and <codeph>ALTER</codeph>
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statements to add comments to the objects.
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</p>
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<p>
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You can view the comment on a database, a table, or a column using the
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<codeph>SHOW</codeph> or <codeph>DESCRIBE</codeph> statement.
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</p>
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<p conref="../shared/impala_common.xml#common/syntax_blurb"/>
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<codeblock>COMMENT ON DATABASE <varname>db_name</varname> IS {'<varname>comment</varname>' | NULL}</codeblock>
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<codeblock>COMMENT ON TABLE [<varname>db_name</varname>.]<varname>table_name</varname> IS {'<varname>comment</varname>' | NULL}</codeblock>
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<codeblock>COMMENT ON COLUMN [<varname>db_name</varname>.]<varname>table_name</varname>.<varname>column_name</varname> IS {'<varname>comment</varname>' | NULL}</codeblock>
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<p>
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<b>Parameters:</b>
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</p>
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<ul>
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<li>
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<varname>db_name</varname>: Specify the database name if not for the current database.
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</li>
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<li>
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<codeph>NULL</codeph>: If given for the comment, removes the existing comment.
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</li>
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<li>
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The <varname>comment</varname> string can be up to 256 characters long.
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</li>
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</ul>
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<p>
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<b>Privileges required:</b>
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</p>
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<p>
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To add a comment, the <codeph>ALTER</codeph> privilege on the object is required.
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</p>
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<p>
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To view a comment, the <codeph>SELECT</codeph>, <codeph>INSERT</codeph>, or
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<codeph>REFRESH</codeph> on the object is required.
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</p>
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<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
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<p>
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<b>Added in:</b> <keyword keyref="impala31"/>
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</p>
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</conbody>
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</concept>
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