[SPARK-51695][SQL][DOCS][FOLLOW-UP] Clarify NULL handling semantics in UNIQUE constraint Javadoc#54357
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[SPARK-51695][SQL][DOCS][FOLLOW-UP] Clarify NULL handling semantics in UNIQUE constraint Javadoc#54357yyanyy wants to merge 1 commit intoapache:masterfrom
yyanyy wants to merge 1 commit intoapache:masterfrom
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…n UNIQUE constraint Javadoc Document NULLS DISTINCT behavior: NULL values are treated as distinct from each other, so rows with NULLs in unique columns never conflict. Also note that UNIQUE allows nullable columns (unlike PRIMARY KEY) and that NULLS NOT DISTINCT is not currently supported. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
| * if and only if no two rows in a table have the same non-null values in the unique columns. | ||
| * Unlike PRIMARY KEY, UNIQUE allows nullable columns. | ||
| * <p> | ||
| * NULL values are treated as distinct from each other (NULLS DISTINCT semantics). Two rows |
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We don’t need to define the suggested behavior in Spark itself. The behavior can be left to the connector implementations.
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What changes were proposed in this pull request?
Document NULLS DISTINCT behavior: NULL values are treated as distinct from each other, so rows with NULLs in unique columns never conflict. Also note that UNIQUE allows nullable columns (unlike PRIMARY KEY) and that NULLS NOT DISTINCT is not currently supported.
Why are the changes needed?
Better javadoc clarity on UNIQUE constraint expectation.
Does this PR introduce any user-facing change?
No
How was this patch tested?
N/A
Was this patch authored or co-authored using generative AI tooling?
Co-Authored-By: Claude Opus 4.6 noreply@anthropic.com