[HIVE-3386] Document how to import NULL values into a table at LanguageManual+Types (\N with Lazy SerDe)

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.9.0
• Component/s: Documentation
• Assignee: Lefty Leverenz
• Reporter: Jakub Holy
• Created: 15/Aug/12 15:01
• Updated: 22/Aug/12 00:20
• Resolved: 22/Aug/12 00:20

Description

The documentation at https://cwiki.apache.org/confluence/display/Hive/LanguageManual+Types should be enhanced as follows:
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Handling of NULL values

Missing values are represented by the special value NULL. To import data with NULL fields, check documentation of the SerDe used by the table. (The default Text Format uses LazySimpleSerDe which interprets the string \N as NULL when importing.)
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Reason:
It's nearly impossible to find out how to make e.g. a string field to be NULL in hive without lot of googling. This is an important thing and should be documented properly at a clearly visible place (the Data Types page seems to be the most logical place to me though LanguageManual+DML would certainly also be a good place).