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https://issues.apache.org/jira/browse/TRAFODION-1610?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16190416#comment-16190416
]
ASF GitHub Bot commented on TRAFODION-1610:
-------------------------------------------
Github user zellerh commented on a diff in the pull request:
https://github.com/apache/incubator-trafodion/pull/1253#discussion_r142530211
--- Diff: core/sql/generator/GenRelUpdate.cpp ---
@@ -292,8 +292,85 @@ static short genUpdExpr(
return 0;
}
-static short genUpdConstraintExpr(Generator *generator)
+// Used to generate update or insert constraint expressions for update
operators
+static short genUpdConstraintExpr(Generator * generator,
+ ItemExpr * constrTree,
+ const ValueIdSet & constraintColumns,
+ ValueIdArray & targetRecExprArray,
+ ex_expr ** targetExpr /* out */)
{
+ ExpGenerator * expGen = generator->getExpGenerator();
+
+ // The Attributes for the table columns refer to the old values of the
column.
+ // The constraints must operate on the new values, though. So we must do
a
+ // switcheroo on the Attributes for the update expression. The target
value IDs
+ // come from targetRecExprArray.
+
+ ValueIdList savedSourceVIDlist;
+ NAList<Attributes*> savedSourceAttrsList(generator->wHeap());
+
+ for (ValueId sourceValId = constraintColumns.init();
+ constraintColumns.next(sourceValId);
+ constraintColumns.advance(sourceValId))
+ {
+ NAColumn * sourceCol =
((IndexColumn*)sourceValId.getItemExpr())->getNAColumn();
+ ValueId targetValId;
+ NABoolean found = FALSE;
+ for (CollIndex ni = 0; (!found) && (ni <
targetRecExprArray.entries()); ni++)
+ {
+ const ItemExpr *assignExpr =
targetRecExprArray[ni].getItemExpr();
+ targetValId =
assignExpr->child(0)->castToItemExpr()->getValueId();
+ NAColumn *targetCol = NULL;
+ if (targetValId.getItemExpr()->getOperatorType() ==
ITM_BASECOLUMN)
+ targetCol =
((BaseColumn*)targetValId.getItemExpr())->getNAColumn();
+ else if (targetValId.getItemExpr()->getOperatorType() ==
ITM_INDEXCOLUMN)
+ targetCol =
((IndexColumn*)targetValId.getItemExpr())->getNAColumn();
+
+ if ((targetCol) &&
+ (targetCol->getColName() == sourceCol->getColName()) &&
+ (targetCol->getHbaseColFam() == sourceCol->getHbaseColFam())
&&
+ (targetCol->getHbaseColQual() ==
sourceCol->getHbaseColQual()) &&
+
(targetCol->getNATable()->getTableName().getQualifiedNameAsAnsiString() ==
+
sourceCol->getNATable()->getTableName().getQualifiedNameAsAnsiString()))
+ {
+ found = TRUE;
+ break;
+ }
+ }
+
+ if (found)
+ {
+ Attributes * sourceValAttr = (generator->addMapInfo(sourceValId,
0))->getAttr();
+ Attributes * targetValAttr = (generator->getMapInfo(targetValId,
0))->getAttr();
+
+ // Save original location attributes so we can change them back
after
+ // generating the update constraint expression
+
+ Attributes * savedValAttr = new(generator->wHeap()) Attributes();
+ savedValAttr->copyLocationAttrs(sourceValAttr);
+ savedSourceAttrsList.insert(savedValAttr);
+ savedSourceVIDlist.insert(sourceValId);
+
+ sourceValAttr->copyLocationAttrs(targetValAttr);
+ }
+
+ }
+
+ // Now that we have remapped the Attributes for the columns to their
values
+ // in the new record, we can generate the update constraint expression.
+
+ expGen->generateExpr(constrTree->getValueId(), ex_expr::exp_SCAN_PRED,
--- End diff --
I don't quite understand what happens when the constraint tree refers to
columns that are not in the assign list, or is the assign list targetRecExpr
always complete? If it's always complete, there would be an optimization to
skip constraints that don't refer to any updated columns.
> Generate constraint expression for update/merge commands
> --------------------------------------------------------
>
> Key: TRAFODION-1610
> URL: https://issues.apache.org/jira/browse/TRAFODION-1610
> Project: Apache Trafodion
> Issue Type: Sub-task
> Components: sql-cmp
> Reporter: Selvaganesan Govindarajan
> Assignee: David Wayne Birdsall
>
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