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https://issues.apache.org/jira/browse/DERBY-3155?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Rick Hillegas updated DERBY-3155:
---------------------------------
Attachment: derby-3155-50-aa-revampDeleteThenRows.diff
Attaching derby-3155-50-aa-revampDeleteThenRows.diff. This patch removes some
special handling of DELETE actions.
DELETE was the first action I coded. The rows which are passed to DELETE
actions are simpler than the rows which are passed to INSERT and UPDATE
actions. That is because a DELETE action just needs columns from the target
table. But INSERT may need complicated expressions built out of source row
columns and UPDATE may need even more complicated expressions built out of
columns from both the target and source tables.
When I coded the DELETE action, I just built some simple machinery to copy
columns from the driving left join. But I had to bite the bullet when I coded
INSERT and UPDATE actions. Then I had to add code to generate the complex
expressions. The copying (for DELETEs) is now redundant since it is a special
case of the more complicated expression evaluation. I have removed the special
copying done for DELETEs. Now DELETE actions use the same expression evaluator
logic as INSERT and UPDATE.
This simplifies and clarifies the code.
Touches the following files:
M java/engine/org/apache/derby/impl/sql/compile/MergeNode.java
M java/engine/org/apache/derby/impl/sql/compile/MatchingClauseNode.java
M
java/engine/org/apache/derby/impl/sql/execute/MatchingClauseConstantAction.java
M
java/engine/org/apache/derby/impl/sql/execute/GenericConstantActionFactory.java
> Support for SQL:2003 MERGE statement
> ------------------------------------
>
> Key: DERBY-3155
> URL: https://issues.apache.org/jira/browse/DERBY-3155
> Project: Derby
> Issue Type: Improvement
> Components: SQL
> Reporter: Trejkaz
> Assignee: Rick Hillegas
> Labels: derby_triage10_10
> Attachments: MergeStatement.html, MergeStatement.html,
> MergeStatement.html, MergeStatement.html, derby-3155-01-ac-grammar.diff,
> derby-3155-02-ag-fixParserWarning.diff,
> derby-3155-03-ae-backingStoreHashtableWithRowLocation.diff,
> derby-3155-03-af-backingStoreHashtableWithRowLocation.diff,
> derby-3155-03-ag-backingStoreHashtableWithRowLocation.diff,
> derby-3155-03-ah-backingStoreHashtableWithRowLocation.diff,
> derby-3155-04-ae-deleteAction.diff, derby-3155-04-af-deleteAction.diff,
> derby-3155-05-aa-triggerTransitionTableAsTarget.diff,
> derby-3155-06-aa-triggerTransitionTableAsSource.diff,
> derby-3155-07-ad-insertAction.diff, derby-3155-08-ah-updateAction.diff,
> derby-3155-09-aa-correlationNames.diff,
> derby-3155-10-aa-correlationNames.diff,
> derby-3155-11-ab-beforeTriggersCantFireMerge.diff,
> derby-3155-12-aa-canOmitInsertColumnList.diff,
> derby-3155-13-aa-allowSystemAndTempTables.diff,
> derby-3155-14-aa-replaceCorrelationNamesOnLeftSideOfSETclauses.diff,
> derby-3155-15-aa-replumbMergeResultSetCleanup.diff,
> derby-3155-16-aa-treatCurrentRowLocationNodeLikeBaseColumnNode.diff,
> derby-3155-17-aa-serializingRowLocations.diff,
> derby-3155-18-aa-basicView.diff,
> derby-3155-19-aa-forbidSubqueriesInMatchedClauses.diff,
> derby-3155-20-aa-reworkColumnMatching.diff,
> derby-3155-21-ac-cleanupAndForbidSynonyms.diff,
> derby-3155-22-ad-testIdentifiersOnLeftSideOfSetClauses.diff,
> derby-3155-23-aa-forbidDerivedColumnLists.diff,
> derby-3155-24-aa-supportParameters.diff,
> derby-3155-25-aa-parametersAsInsertValues.diff,
> derby-3155-26-aa-copyRowLocationForIndexScans.diff,
> derby-3155-27-aa-adjustMatchingRefinements.diff,
> derby-3155-28-aa-cardinalityViolations.diff,
> derby-3155-29-aa-missingSchema.diff,
> derby-3155-30-ab-moreCorrelationNames.diff,
> derby-3155-31-aa-deletePrivs.diff, derby-3155-32-aa-newTestFunction.diff,
> derby-3155-33-ab-insertPrivs.diff, derby-3155-34-aa-updatePrivs.diff,
> derby-3155-34-ab-updatePrivs.diff, derby-3155-35-aa-allPrivsTest.diff,
> derby-3155-36-aa-lockModeComment.diff, derby-3155-37-aa-printSubNodes.diff,
> derby-3155-38-aa-datatypes.diff, derby-3155-39-aa-fixBuild.diff,
> derby-3155-40-aa-bigLobs.diff, derby-3155-41-aa-nullGeneratedColumns.diff,
> derby-3155-42-aa-triggersAndGeneratedColumns.diff,
> derby-3155-43-aa-eliminateDuplicateColumnRefs.diff,
> derby-3155-44-aa-lobsInTriggers.diff, derby-3155-45-aa-serialization.diff,
> derby-3155-46-aa-deferredDeletes.diff, derby-3155-47-aa-collations.diff,
> derby-3155-48-aa-indexScan.diff, derby-3155-49-aa-cleanup1.diff,
> derby-3155-50-aa-revampDeleteThenRows.diff
>
>
> A relatively common piece of logic in a database application is to check for
> a row's existence and then either update or insert depending on its existence.
> SQL:2003 added a MERGE statement to perform this operation. It looks like
> this:
> MERGE INTO table_name USING table_name ON (condition)
> WHEN MATCHED THEN UPDATE SET column1 = value1 [, column2 = value2 ...]
> WHEN NOT MATCHED THEN INSERT column1 [, column2 ...] VALUES (value1 [,
> value2 ...])
> At the moment, the only workaround for this would be to write a stored
> procedure to do the same operation, or to implement the logic client-side.
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