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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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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 be set to +^A+ and the record delimiter will be set to +\n+ to be consistent
with Hive's defaults. 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 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+ source table. You can control the output table name with the +\--hive-table+
option. option.