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Posted to dev@hive.apache.org by "Jakub Holy (JIRA)" <ji...@apache.org> on 2012/08/15 17:02:38 UTC
[jira] [Created] (HIVE-3386) Document how to import NULL values
into a table at LanguageManual+Types (\N with Lazy SerDe)
Jakub Holy created HIVE-3386:
--------------------------------
Summary: Document how to import NULL values into a table at LanguageManual+Types (\N with Lazy SerDe)
Key: HIVE-3386
URL: https://issues.apache.org/jira/browse/HIVE-3386
Project: Hive
Issue Type: Improvement
Components: Documentation
Affects Versions: 0.9.0
Reporter: Jakub Holy
The documentation at https://cwiki.apache.org/confluence/display/Hive/LanguageManual+Types should be enhanced as follows:
---
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.)
---
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).
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[jira] [Assigned] (HIVE-3386) Document how to import NULL values
into a table at LanguageManual+Types (\N with Lazy SerDe)
Posted by "Lefty Leverenz (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HIVE-3386?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Lefty Leverenz reassigned HIVE-3386:
------------------------------------
Assignee: Lefty Leverenz
> Document how to import NULL values into a table at LanguageManual+Types (\N with Lazy SerDe)
> --------------------------------------------------------------------------------------------
>
> Key: HIVE-3386
> URL: https://issues.apache.org/jira/browse/HIVE-3386
> Project: Hive
> Issue Type: Improvement
> Components: Documentation
> Affects Versions: 0.9.0
> Reporter: Jakub Holy
> Assignee: Lefty Leverenz
>
> The documentation at https://cwiki.apache.org/confluence/display/Hive/LanguageManual+Types should be enhanced as follows:
> ---
> 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.)
> ---
> 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).
--
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[jira] [Resolved] (HIVE-3386) Document how to import NULL values
into a table at LanguageManual+Types (\N with Lazy SerDe)
Posted by "Lefty Leverenz (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HIVE-3386?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Lefty Leverenz resolved HIVE-3386.
----------------------------------
Resolution: Fixed
Changed in the wikidoc.
> Document how to import NULL values into a table at LanguageManual+Types (\N with Lazy SerDe)
> --------------------------------------------------------------------------------------------
>
> Key: HIVE-3386
> URL: https://issues.apache.org/jira/browse/HIVE-3386
> Project: Hive
> Issue Type: Improvement
> Components: Documentation
> Affects Versions: 0.9.0
> Reporter: Jakub Holy
> Assignee: Lefty Leverenz
>
> The documentation at https://cwiki.apache.org/confluence/display/Hive/LanguageManual+Types should be enhanced as follows:
> ---
> 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.)
> ---
> 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).
--
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[jira] [Commented] (HIVE-3386) Document how to import NULL values
into a table at LanguageManual+Types (\N with Lazy SerDe)
Posted by "Lefty Leverenz (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HIVE-3386?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13436660#comment-13436660 ]
Lefty Leverenz commented on HIVE-3386:
--------------------------------------
I added the new section verbatim to [Data Types|https://cwiki.apache.org/confluence/display/Hive/LanguageManual+Types] in the wiki but wonder why you used initial capitals for Text Format.
Does this information also belong in "Inserting data into Hive Tables from queries" in [DML|https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DML] as another bullet item in the Notes? Or should a note just refer to the Types doc "for information about types and NULL values"?
Does the information also belong in the DDL docs? Wikidoc [DDL|https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL] already points to Types from its "Create Table" section, but in the Hive xdocs there's another DDL doc (misnamed [DML|http://hive.apache.org/docs/r0.9.0/language_manual/data-manipulation-statements.html]) that could include this information in its "Using SerDes" section or just point to the Types wikidoc.
> Document how to import NULL values into a table at LanguageManual+Types (\N with Lazy SerDe)
> --------------------------------------------------------------------------------------------
>
> Key: HIVE-3386
> URL: https://issues.apache.org/jira/browse/HIVE-3386
> Project: Hive
> Issue Type: Improvement
> Components: Documentation
> Affects Versions: 0.9.0
> Reporter: Jakub Holy
> Assignee: Lefty Leverenz
>
> The documentation at https://cwiki.apache.org/confluence/display/Hive/LanguageManual+Types should be enhanced as follows:
> ---
> 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.)
> ---
> 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).
--
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