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SQOOP-598. Document NULL substitution string changes for HIVE import.

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(Jarek Jarcec Cecho via Abhijeet Gaikwad)
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Abhijeet Gaikwad 2012-09-10 19:18:58 +05:30
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commit 2a2596b7d5
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src/docs/user/hive.txt
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@ -70,6 +70,18 @@ not set any delimiters and do use +\--hive-import+, the field delimiter will
be set to +^A+ and the record delimiter will be set to +\n+ to be consistent
with Hive's defaults.
Sqoop will by default import NULL values as string +null+. Hive is however
using string +\N+ to denote +NULL+ values and therefore predicates dealing
with +NULL+ (like +IS NULL+) will not work correctly. You should append
parameters +\--null-string+ and +\--null-non-string+ in case of import job or
+--input-null-string+ and +--input-null-non-string+ in case of an export job if
you wish to properly preserve +NULL+ values. Because sqoop is using those
parameters in generated code, you need to properly escape value +\N+ to +\\N+:
----
$ sqoop import ... --null-string '\\N' --null-non-string '\\N'
----
The table name used in Hive is, by default, the same as that of the
source table. You can control the output table name with the +\--hive-table+
option.