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From: Thomas White <tomwhite@apache.org> git-svn-id: https://svn.apache.org/repos/asf/incubator/sqoop/trunk@1149855 13f79535-47bb-0310-9956-ffa450edef68
63 lines
2.8 KiB
Plaintext
63 lines
2.8 KiB
Plaintext
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////
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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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, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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////
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Importing Data Into Hive
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------------------------
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Sqoop's primary function is to upload your data into files in HDFS. If
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you have a Hive metastore associated with your HDFS cluster, Sqoop can
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also import the data into Hive by generating and executing a +CREATE
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TABLE+ statement to define the data's layout in Hive. Importing data
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into Hive is as simple as adding the *+--hive-import+* option to your
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Sqoop command line.
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After your data is imported into HDFS, Sqoop will generate a Hive
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script containing a +CREATE TABLE+ operation defining your columns using
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Hive's types, and a +LOAD DATA INPATH+ statement to move the data files
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into Hive's warehouse directory. The script will be executed by
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calling the installed copy of hive on the machine where Sqoop is run.
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If you have multiple Hive installations, or +hive+ is not in your
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+$PATH+ use the *+--hive-home+* option to identify the Hive installation
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directory. Sqoop will use +$HIVE_HOME/bin/hive+ from here.
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NOTE: This function is incompatible with +--as-sequencefile+.
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Hive's text parser does not know how to support escaping or enclosing
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characters. Sqoop will print a warning if you use +--escaped-by+,
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+--enclosed-by+, or +--optionally-enclosed-by+ since Hive does not know
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how to parse these. It will pass the field and record terminators through
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to Hive. If you do not set any delimiters and do use +--hive-import+,
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the field delimiter will be set to +^A+ and the record delimiter will
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be set to +\n+ to be consistent with Hive's defaults.
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The table name used in Hive is, by default, the same as that of the
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source table. You can control the output table name with the +--hive-table+
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option.
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Hive's Type System
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~~~~~~~~~~~~~~~~~~
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Hive users will note that there is not a one-to-one mapping between
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SQL types and Hive types. In general, SQL types that do not have a
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direct mapping (e.g., +DATE+, +TIME+, and +TIMESTAMP+) will be coerced to
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+STRING+ in Hive. The +NUMERIC+ and +DECIMAL+ SQL types will be coerced to
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+DOUBLE+. In these cases, Sqoop will emit a warning in its log messages
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informing you of the loss of precision.
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