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• LITERAL

• DATE TIME VALUE FUNCTION i.e. CURRENT_TIME, CURRENT_DATE

• CURRENT_USER()

• CURRENT_DATABASE()

• NULL

INSERT

Anytime user doesn’t specify a value explicitly for a column its default value will be used if defined e.g

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• ALTER TABLE CHANGE COLUMN

• ALTER TABLE DROP CONSTRAINT

Restrictions

• Hive will have strict type rules for defining default value i.e. default value will have to be exact type as column type.
• Default with Complex data types i.e Array, Struct, Map and Union are not allowed.

Proposed Design

Currently if INSERT query is missing a value in INSERT i.e. if user hasn’t specified a value for column Hive uses ‘NULL’ as default. Hive compiler detects this missing column value at compile time and inserts a NULL. We propose to update this logic to check for default and use that instead of NULL value.

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