Class SelectNode
java.lang.Object
org.apache.derby.impl.sql.compile.QueryTreeNode
org.apache.derby.impl.sql.compile.ResultSetNode
org.apache.derby.impl.sql.compile.SelectNode
- All Implemented Interfaces:
Visitable
A SelectNode represents the result set for any of the basic DML
operations: SELECT, INSERT, UPDATE, and DELETE. (A RowResultSetNode
will be used for an INSERT with a VALUES clause.) For INSERT - SELECT,
any of the fields in a SelectNode can be used (the SelectNode represents
the SELECT statement in the INSERT - SELECT). For UPDATE and
DELETE, there will be one table in the fromList, and the groupByList
fields will be null. For both INSERT and UPDATE,
the resultColumns in the selectList will contain the names of the columns
being inserted into or updated.
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Nested Class Summary
Nested classes/interfaces inherited from class org.apache.derby.impl.sql.compile.ResultSetNode
ResultSetNode.QueryExpressionClauses
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate boolean
(package private) FromList
List of tables in the FROM clause of this SELECT(package private) GroupByList
List of result columns in GROUP BY clauseprivate List
<AggregateNode> Aggregates in the HAVING clause.(package private) ValueNode
(package private) SubqueryList
private boolean
private int
private boolean
(package private) boolean
(package private) ValueNode
(package private) boolean
(package private) OptimizerPlan
Full plan for this SELECT as specified in an optimizer overrideprivate FromList
(package private) ResultSetNode.QueryExpressionClauses
private List
<AggregateNode> Aggregates in the SELECT list.(package private) SubqueryList
(package private) FromTable
private boolean
User specified a group by without aggregates and we turned it into a select distinctprivate List
<AggregateNode> Aggregates in the WHERE clause.(package private) ValueNode
The ValueNode for the WHERE clause must represent a boolean expression.(package private) PredicateList
(package private) SubqueryList
(package private) List
<WindowFunctionNode> List of window function calls (e.g.(package private) WindowList
List of windows.Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode
AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_CYCLE, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX
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Constructor Summary
ConstructorsConstructorDescriptionSelectNode
(ResultColumnList selectList, FromList fromList, ValueNode whereClause, GroupByList groupByList, ValueNode havingClause, WindowList windowDefinitionList, OptimizerPlan overridingPlan, ContextManager cm) -
Method Summary
Modifier and TypeMethodDescription(package private) void
Accept the visitor for all visitable children of this node.private WindowList
(package private) ResultSetNode
addNewPredicate
(Predicate predicate) Add a new predicate to the list.(package private) void
bindExpressions
(FromList fromListParam) Bind the expressions in this SelectNode.(package private) void
bindExpressionsWithTables
(FromList fromListParam) Bind the expressions in this ResultSetNode if it has tables.(package private) ResultSetNode
bindNonVTITables
(DataDictionary dataDictionary, FromList fromListParam) Bind the tables in this SelectNode.(package private) void
bindResultColumns
(TableDescriptor targetTableDescriptor, FromVTI targetVTI, ResultColumnList targetColumnList, DMLStatementNode statement, FromList fromListParam) Bind the result columns for this ResultSetNode to a base table.(package private) void
bindResultColumns
(FromList fromListParam) Bind the result columns of this ResultSetNode when there is no base table to bind them to.(package private) void
bindTargetExpressions
(FromList fromListParam) Bind the expressions in the target list.(package private) void
bindUntypedNullsToResultColumns
(ResultColumnList bindingRCL) Bind any untyped null nodes to the types in the given ResultColumnList.(package private) static void
checkNoWindowFunctions
(QueryTreeNode clause, String clauseName) (package private) void
(package private) void
decrementLevel
(int decrement) Decrement (query block) level (0-based) for all of the tables in this ResultSet tree.(package private) ResultSetNode
ensurePredicateList
(int numTables) Ensure that the top of the RSN tree has a PredicateList.(package private) ColumnReference
findColumnReferenceInResult
(String colName) Find colName in the result columns and return underlying columnReference.(package private) boolean
flattenableInFromSubquery
(FromList fromList) Evaluate whether or not the subquery in a FromSubquery is flattenable.(package private) ResultSetNode
genProjectRestrict
(int origFromListSize) Replace this SelectNode with a ProjectRestrictNode, since it has served its purpose.(package private) FromTable
Assumes that isCursorUpdatable has been called, and that it is only called for updatable cursors.(package private) CostEstimate
Get the final CostEstimate for this SelectNode.(package private) FromList
Return the fromList for this SelectNode.(package private) FromTable
getFromTableByName
(String name, String schemaName, boolean exactMatch) Determine whether or not the specified name is an exposed name in the current query block.private Optimizer
getOptimizer
(OptimizableList optList, OptimizablePredicateList predList, DataDictionary dataDictionary, RequiredRowOrdering requiredRowOrdering, OptimizerPlan overridingPlan) Get an optimizer to use for this SelectNode.(package private) SubqueryList
Return the selectSubquerys for this SelectNode.(package private) ValueNode
Return the whereClause for this SelectNode.(package private) PredicateList
Return the wherePredicates for this SelectNode.(package private) SubqueryList
Return the whereSubquerys for this SelectNode.(package private) boolean
(package private) boolean
(package private) boolean
(package private) boolean
Used by SubqueryNode to avoid flattening of a subquery if a window is defined on it.private boolean
isOrderedResult
(ResultColumnList resultColumns, ResultSetNode newTopRSN, boolean permuteOrdering) Is the result of this node an ordered result set.(package private) boolean
Determine if this select is updatable or not, for a cursor.(package private) void
(package private) ResultSetNode
Modify the access paths according to the choices the optimizer made.(package private) ResultSetNode
modifyAccessPaths
(PredicateList predList) Modify the access paths according to the decisions the optimizer made.private ValueNode
normExpressions
(ValueNode boolClause) Put the expression trees in conjunctive normal form(package private) ResultSetNode
optimize
(DataDictionary dataDictionary, PredicateList predicateList, double outerRows) Optimize this SelectNode.private void
performTransitiveClosure
(int numTables) Peform the various types of transitive closure on the where clause.(package private) ResultSetNode
preprocess
(int numTables, GroupByList gbl, FromList fl) Put a ProjectRestrictNode on top of each FromTable in the FromList.(package private) void
printSubNodes
(int depth) Prints the sub-nodes of this object.(package private) void
pushExpressionsIntoSelect
(Predicate predicate) Push an expression into this SELECT (and possibly down into one of the tables in the FROM list).(package private) void
pushOffsetFetchFirst
(ValueNode offset, ValueNode fetchFirst, boolean hasJDBClimitClause) Push down the offset and fetch first parameters to this node.(package private) void
pushOrderByList
(OrderByList orderByList) Push the order by list down from the cursor node into its child result set so that the optimizer has all of the information that it needs to consider sort avoidance.void
Set up a new level for order by and fetch/offset clauses.boolean
Return true if the node references SESSION schema tables (temporary or permanent)(package private) boolean
referencesTarget
(String name, boolean baseTable) Search to see if a query references the specifed table name.(package private) void
Check for (and reject) ?(package private) void
replaceOrForbidDefaults
(TableDescriptor ttd, ResultColumnList tcl, boolean allowDefaults) Replace any DEFAULTs with the associated tree for the default if allowed, or flag (when inside top level set operator nodes).(package private) boolean
Return whether or not this ResultSet tree is guaranteed to return at most 1 row based on heuristics.(package private) String
(package private) boolean
subqueryReferencesTarget
(String name, boolean baseTable) Return whether or not this ResultSetNode contains a subquery with a reference to the specified target table.toString()
Convert this object to a String.(package private) boolean
uniqueSubquery
(boolean additionalEQ) Determine whether or not this subquery, the SelectNode is in a subquery, can be flattened into the outer query block based on a uniqueness condition.(package private) int
Get the lock mode for the target of an update statement (a delete or update).(package private) void
verifySelectStarSubquery
(FromList outerFromList, int subqueryType) Verify that a SELECT * is valid for this type of subquery.Methods inherited from class org.apache.derby.impl.sql.compile.ResultSetNode
adjustForSortElimination, adjustForSortElimination, assignResultSetNumber, bindVTITables, changeAccessPath, columnTypesAndLengthsMatch, considerMaterialization, enhanceRCLForInsert, fillInReferencedTableMap, generateNormalizationResultSet, generateResultSet, genProjectRestrict, genProjectRestrictForReordering, getAllResultColumns, getCandidateFinalCostEstimate, getCostEstimate, getMatchingColumn, getNewCostEstimate, getOptimizer, getOptimizerImpl, getRCLForInsert, getReferencedTableMap, getResultColumns, getResultSetNumber, getScratchCostEstimate, isCursorTargetTable, isInsertSource, isNotExists, isOneRowResultSet, isOrderedOn, isPossibleDistinctScan, isStatementResultSet, LOJgetReferencedTables, makeResultDescription, makeResultDescriptors, markAsCursorTargetTable, markForDistinctScan, markStatementResultSet, notCursorTargetTable, notFlattenableJoin, numDistinctAggregates, parseDefault, performMaterialization, printQueryExpressionSuffixClauses, projectResultColumns, rejectXMLValues, renameGeneratedResultNames, setCandidateFinalCostEstimate, setCostEstimate, setCursorTargetTable, setInsertSource, setOptimizer, setReferencedTableMap, setResultColumns, setResultSetNumber, setResultToBooleanTrueNode, setScratchCostEstimate, setTableConstructorTypes
Methods inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode
accept, addTag, addUDTUsagePriv, addUDTUsagePriv, bindOffsetFetch, bindRowMultiSet, bindUserCatalogType, bindUserType, checkReliability, checkReliability, convertDefaultNode, copyTagsFrom, createTypeDependency, debugFlush, debugPrint, disablePrivilegeCollection, formatNodeString, generate, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContext, getContextManager, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getLongProperty, getNullNode, getOffsetOrderedNodes, getOptimizerFactory, getOptimizerTracer, getParameterTypes, getSchemaDescriptor, getSchemaDescriptor, getStatementType, getTableDescriptor, getTypeCompiler, getUDTDesc, isAtomic, isPrivilegeCollectionRequired, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, makeTableName, nodeHeader, optimizerTracingIsOn, orReliability, parseSearchCondition, parseStatement, printLabel, resolveTableToSynonym, setBeginOffset, setEndOffset, setRefActionInfo, stackPrint, taggedWith, treePrint, treePrint, verifyClassExist
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Field Details
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fromList
FromList fromListList of tables in the FROM clause of this SELECT -
targetTable
FromTable targetTable -
selectAggregates
Aggregates in the SELECT list. -
whereAggregates
Aggregates in the WHERE clause. -
havingAggregates
Aggregates in the HAVING clause. -
whereClause
ValueNode whereClauseThe ValueNode for the WHERE clause must represent a boolean expression. The binding phase will enforce this - the parser does not have enough information to enforce it in all cases (for example, user methods that return boolean). -
originalWhereClause
ValueNode originalWhereClause -
groupByList
GroupByList groupByListList of result columns in GROUP BY clause -
windows
WindowList windowsList of windows. -
overridingPlan
OptimizerPlan overridingPlanFull plan for this SELECT as specified in an optimizer override -
windowFuncCalls
List<WindowFunctionNode> windowFuncCallsList of window function calls (e.g. ROW_NUMBER, AVG(i), DENSE_RANK). -
wasGroupBy
private boolean wasGroupByUser specified a group by without aggregates and we turned it into a select distinct -
orderByQuery
boolean orderByQuery -
qec
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wherePredicates
PredicateList wherePredicates -
selectSubquerys
SubqueryList selectSubquerys -
whereSubquerys
SubqueryList whereSubquerys -
havingSubquerys
SubqueryList havingSubquerys -
bindTargetListOnly
private boolean bindTargetListOnly -
isDistinct
private boolean isDistinct -
orderByAndDistinctMerged
private boolean orderByAndDistinctMerged -
originalWhereClauseHadSubqueries
boolean originalWhereClauseHadSubqueries -
preJoinFL
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havingClause
ValueNode havingClause -
nestingLevel
private int nestingLevel
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Constructor Details
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SelectNode
SelectNode(ResultColumnList selectList, FromList fromList, ValueNode whereClause, GroupByList groupByList, ValueNode havingClause, WindowList windowDefinitionList, OptimizerPlan overridingPlan, ContextManager cm) throws StandardException - Throws:
StandardException
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Method Details
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addInlinedWindowDefinition
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toString
Convert this object to a String. See comments in QueryTreeNode.java for how this should be done for tree printing.- Overrides:
toString
in classResultSetNode
- Returns:
- This object as a String
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statementToString
String statementToString() -
makeDistinct
void makeDistinct() -
clearDistinct
void clearDistinct() -
hasDistinct
boolean hasDistinct() -
printSubNodes
void printSubNodes(int depth) Prints the sub-nodes of this object. See QueryTreeNode.java for how tree printing is supposed to work.- Overrides:
printSubNodes
in classResultSetNode
- Parameters:
depth
- The depth of this node in the tree
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getFromList
FromList getFromList()Return the fromList for this SelectNode.- Overrides:
getFromList
in classResultSetNode
- Returns:
- FromList The fromList for this SelectNode.
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findColumnReferenceInResult
Find colName in the result columns and return underlying columnReference. Note that this function returns null if there are more than one FromTable for this SelectNode and the columnReference needs to be directly under the resultColumn. So having an expression under the resultSet would cause returning null.- Parameters:
colName
- Name of the column- Returns:
- ColumnReference ColumnReference to the column, if found
- Throws:
StandardException
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getWhereClause
ValueNode getWhereClause()Return the whereClause for this SelectNode.- Returns:
- ValueNode The whereClause for this SelectNode.
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getWherePredicates
PredicateList getWherePredicates()Return the wherePredicates for this SelectNode.- Returns:
- PredicateList The wherePredicates for this SelectNode.
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getSelectSubquerys
SubqueryList getSelectSubquerys()Return the selectSubquerys for this SelectNode.- Returns:
- SubqueryList The selectSubquerys for this SelectNode.
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getWhereSubquerys
SubqueryList getWhereSubquerys()Return the whereSubquerys for this SelectNode.- Returns:
- SubqueryList The whereSubquerys for this SelectNode.
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bindNonVTITables
ResultSetNode bindNonVTITables(DataDictionary dataDictionary, FromList fromListParam) throws StandardException Bind the tables in this SelectNode. This includes getting their TableDescriptors from the DataDictionary and numbering the FromTables. NOTE: Because this node represents the top of a new query block, we bind both the non VTI and VTI tables under this node in this method call.- Overrides:
bindNonVTITables
in classResultSetNode
- Parameters:
dataDictionary
- The DataDictionary to use for bindingfromListParam
- FromList to use/append to.- Returns:
- ResultSetNode
- Throws:
StandardException
- Thrown on error
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bindExpressions
Bind the expressions in this SelectNode. This means binding the sub-expressions, as well as figuring out what the return type is for each expression.- Overrides:
bindExpressions
in classResultSetNode
- Parameters:
fromListParam
- FromList to use/append to.- Throws:
StandardException
- Thrown on error
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bindExpressionsWithTables
Bind the expressions in this ResultSetNode if it has tables. This means binding the sub-expressions, as well as figuring out what the return type is for each expression.- Overrides:
bindExpressionsWithTables
in classResultSetNode
- Parameters:
fromListParam
- FromList to use/append to.- Throws:
StandardException
- Thrown on error
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bindTargetExpressions
Bind the expressions in the target list. This means binding the sub-expressions, as well as figuring out what the return type is for each expression. This is useful for EXISTS subqueries, where we need to validate the target list before blowing it away and replacing it with a SELECT true.- Overrides:
bindTargetExpressions
in classResultSetNode
- Throws:
StandardException
- Thrown on error
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bindResultColumns
Bind the result columns of this ResultSetNode when there is no base table to bind them to. This is useful for SELECT statements, where the result columns get their types from the expressions that live under them.- Overrides:
bindResultColumns
in classResultSetNode
- Parameters:
fromListParam
- FromList to use/append to.- Throws:
StandardException
- Thrown on error
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bindResultColumns
void bindResultColumns(TableDescriptor targetTableDescriptor, FromVTI targetVTI, ResultColumnList targetColumnList, DMLStatementNode statement, FromList fromListParam) throws StandardException Bind the result columns for this ResultSetNode to a base table. This is useful for INSERT and UPDATE statements, where the result columns get their types from the table being updated or inserted into. If a result column list is specified, then the verification that the result column list does not contain any duplicates will be done when binding them by name.- Overrides:
bindResultColumns
in classResultSetNode
- Parameters:
targetTableDescriptor
- The TableDescriptor for the table being updated or inserted intotargetColumnList
- For INSERT statements, the user does not have to supply column names (for example, "insert into t values (1,2,3)". When this parameter is null, it means that the user did not supply column names, and so the binding should be done based on order. When it is not null, it means do the binding by name, not position.statement
- Calling DMLStatementNode (Insert or Update)fromListParam
- FromList to use/append to.- Throws:
StandardException
- Thrown on error
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pushExpressionsIntoSelect
Push an expression into this SELECT (and possibly down into one of the tables in the FROM list). This is useful when trying to push predicates into unflattened views or derived tables.- Parameters:
predicate
- The predicate that we attempt to push- Throws:
StandardException
- Thrown on error
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verifySelectStarSubquery
Verify that a SELECT * is valid for this type of subquery.- Overrides:
verifySelectStarSubquery
in classResultSetNode
- Parameters:
outerFromList
- The FromList from the outer query block(s)subqueryType
- The subquery type- Throws:
StandardException
- Thrown on error
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getFromTableByName
FromTable getFromTableByName(String name, String schemaName, boolean exactMatch) throws StandardException Determine whether or not the specified name is an exposed name in the current query block.- Overrides:
getFromTableByName
in classResultSetNode
- Parameters:
name
- The specified name to search for as an exposed name.schemaName
- Schema name, if non-null.exactMatch
- Whether or not we need an exact match on specified schema and table names or match on table id.- Returns:
- The FromTable, if any, with the exposed name.
- Throws:
StandardException
- Thrown on error
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rejectParameters
Check for (and reject) ? parameters directly under the ResultColumns. This is done for SELECT statements.- Overrides:
rejectParameters
in classResultSetNode
- Throws:
StandardException
- Thrown if a ? parameter found directly under a ResultColumn
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pushQueryExpressionSuffix
public void pushQueryExpressionSuffix()Description copied from class:ResultSetNode
Set up a new level for order by and fetch/offset clauses. See Javadoc forResultSetNode.QueryExpressionClauses
. Overridden by implementors of pushOrderByNode, pushOffsetFetchFirst.- Overrides:
pushQueryExpressionSuffix
in classResultSetNode
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pushOrderByList
Push the order by list down from the cursor node into its child result set so that the optimizer has all of the information that it needs to consider sort avoidance.- Overrides:
pushOrderByList
in classResultSetNode
- Parameters:
orderByList
- The order by list
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pushOffsetFetchFirst
Push down the offset and fetch first parameters to this node.- Overrides:
pushOffsetFetchFirst
in classResultSetNode
- Parameters:
offset
- the OFFSET, if anyfetchFirst
- the OFFSET FIRST, if anyhasJDBClimitClause
- true if the clauses were added by (and have the semantics of) a JDBC limit clause
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preprocess
Put a ProjectRestrictNode on top of each FromTable in the FromList. ColumnReferences must continue to point to the same ResultColumn, so that ResultColumn must percolate up to the new PRN. However, that ResultColumn will point to a new expression, a VirtualColumnNode, which points to the FromTable and the ResultColumn that is the source for the ColumnReference. (The new PRN will have the original of the ResultColumnList and the ResultColumns from that list. The FromTable will get shallow copies of the ResultColumnList and its ResultColumns. ResultColumn.expression will remain at the FromTable, with the PRN getting a new VirtualColumnNode for each ResultColumn.expression.) We then project out the non-referenced columns. If there are no referenced columns, then the PRN's ResultColumnList will consist of a single ResultColumn whose expression is 1.- Overrides:
preprocess
in classResultSetNode
- Parameters:
numTables
- The number of tables in the DML Statementgbl
- The outer group by list, if anyfl
- The from list, if any- Returns:
- The generated ProjectRestrictNode atop the original FromTable.
- Throws:
StandardException
- Thrown on error
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performTransitiveClosure
Peform the various types of transitive closure on the where clause. The 2 types are transitive closure on join clauses and on search clauses. Join clauses will be processed first to maximize benefit for search clauses.- Parameters:
numTables
- The number of tables in the query- Throws:
StandardException
- Thrown on error
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normExpressions
Put the expression trees in conjunctive normal form- Parameters:
boolClause
- clause to normalize- Throws:
StandardException
- Thrown on error
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addNewPredicate
Add a new predicate to the list. This is useful when doing subquery transformations, when we build a new predicate with the left side of the subquery operator and the subquery's result column.- Overrides:
addNewPredicate
in classResultSetNode
- Parameters:
predicate
- The predicate to add- Returns:
- ResultSetNode The new top of the tree.
- Throws:
StandardException
- Thrown on error
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flattenableInFromSubquery
Evaluate whether or not the subquery in a FromSubquery is flattenable. Currently, a FSqry is flattenable if all of the following are true: o Subquery is a SelectNode. (ie, not a RowResultSetNode or a UnionNode) o It contains a single table in its FROM list. o It contains no subqueries in the SELECT list. o It does not contain a group by or having clause o It does not contain aggregates. o It is not a DISTINCT. o It does not have an ORDER BY clause (pushed from FromSubquery).- Overrides:
flattenableInFromSubquery
in classResultSetNode
- Parameters:
fromList
- The outer from list- Returns:
- boolean Whether or not the FromSubquery is flattenable.
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genProjectRestrict
Replace this SelectNode with a ProjectRestrictNode, since it has served its purpose.- Overrides:
genProjectRestrict
in classResultSetNode
- Parameters:
origFromListSize
- The size of the original FROM list, before generation of join tree.- Returns:
- ResultSetNode new ResultSetNode atop the query tree.
- Throws:
StandardException
- Thrown on error
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isOrderedResult
private boolean isOrderedResult(ResultColumnList resultColumns, ResultSetNode newTopRSN, boolean permuteOrdering) throws StandardException Is the result of this node an ordered result set. An ordered result set means that the results from this node will come in a known sorted order. This means that the data is ordered according to the order of the elements in the RCL. Today, the data is considered ordered if: o The RCL is composed entirely of CRs or ConstantNodes o The underlying tree is ordered on the CRs in the order in which they appear in the RCL, taking equality predicates into account. Future Enhancements: o The prefix will not be required to be in order. (We will need to reorder the RCL and generate a PRN with an RCL in the expected order.)- Returns:
- boolean Whether or not this node returns an ordered result set.
- Throws:
StandardException
- Thrown on error
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ensurePredicateList
Ensure that the top of the RSN tree has a PredicateList.- Overrides:
ensurePredicateList
in classResultSetNode
- Parameters:
numTables
- The number of tables in the query.- Returns:
- ResultSetNode A RSN tree with a node which has a PredicateList on top.
- Throws:
StandardException
- Thrown on error
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optimize
ResultSetNode optimize(DataDictionary dataDictionary, PredicateList predicateList, double outerRows) throws StandardException Optimize this SelectNode. This means choosing the best access path for each table, among other things.- Overrides:
optimize
in classResultSetNode
- Parameters:
dataDictionary
- The DataDictionary to use for optimizationpredicateList
- The predicate list to optimize againstouterRows
- The number of outer joining rows- Returns:
- ResultSetNode The top of the optimized tree
- Throws:
StandardException
- Thrown on error
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getOptimizer
private Optimizer getOptimizer(OptimizableList optList, OptimizablePredicateList predList, DataDictionary dataDictionary, RequiredRowOrdering requiredRowOrdering, OptimizerPlan overridingPlan) throws StandardException Get an optimizer to use for this SelectNode. Only get it once - subsequent calls return the same optimizer.- Throws:
StandardException
- Thrown on error
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modifyAccessPaths
Modify the access paths according to the decisions the optimizer made. This can include adding project/restrict nodes, index-to-base-row nodes, etc.- Overrides:
modifyAccessPaths
in classResultSetNode
- Parameters:
predList
- A list of optimizable predicates that should be pushed to this ResultSetNode, as determined by optimizer.- Returns:
- The modified query tree
- Throws:
StandardException
- Thrown on error
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modifyAccessPaths
Modify the access paths according to the choices the optimizer made.- Overrides:
modifyAccessPaths
in classResultSetNode
- Returns:
- A QueryTree with the necessary modifications made
- Throws:
StandardException
- Thrown on error
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getFinalCostEstimate
Get the final CostEstimate for this SelectNode.- Overrides:
getFinalCostEstimate
in classResultSetNode
- Returns:
- The final CostEstimate for this SelectNode, which is the final cost estimate for the best join order of this SelectNode's optimizer.
- Throws:
StandardException
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isUpdatableCursor
Determine if this select is updatable or not, for a cursor.- Overrides:
isUpdatableCursor
in classResultSetNode
- Throws:
StandardException
- Thrown on error
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getCursorTargetTable
FromTable getCursorTargetTable()Assumes that isCursorUpdatable has been called, and that it is only called for updatable cursors.- Overrides:
getCursorTargetTable
in classResultSetNode
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referencesTarget
Search to see if a query references the specifed table name.- Overrides:
referencesTarget
in classResultSetNode
- Parameters:
name
- Table name (String) to search for.baseTable
- Whether or not name is for a base table- Returns:
- true if found, else false
- Throws:
StandardException
- Thrown on error
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subqueryReferencesTarget
Return whether or not this ResultSetNode contains a subquery with a reference to the specified target table.- Overrides:
subqueryReferencesTarget
in classResultSetNode
- Parameters:
name
- The table name.baseTable
- Whether or not table is a base table.- Returns:
- boolean Whether or not a reference to the table was found.
- Throws:
StandardException
- Thrown on error
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bindUntypedNullsToResultColumns
Bind any untyped null nodes to the types in the given ResultColumnList.- Overrides:
bindUntypedNullsToResultColumns
in classResultSetNode
- Parameters:
bindingRCL
- The ResultColumnList with the types to bind to.- Throws:
StandardException
- Thrown on error
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decrementLevel
void decrementLevel(int decrement) Decrement (query block) level (0-based) for all of the tables in this ResultSet tree. This is useful when flattening a subquery.- Specified by:
decrementLevel
in classResultSetNode
- Parameters:
decrement
- The amount to decrement by.
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uniqueSubquery
Determine whether or not this subquery, the SelectNode is in a subquery, can be flattened into the outer query block based on a uniqueness condition. A uniqueness condition exists when we can guarantee that at most 1 row will qualify in each table in the subquery. This is true if every table in the from list is (a base table and the set of columns from the table that are in equality comparisons with expressions that do not include a column from the same table is a superset of any unique index on the table) or an ExistsBaseTable.- Parameters:
additionalEQ
- Whether or not the column returned by this select, if it is a ColumnReference, is in an equality comparison.- Returns:
- Whether or not this subquery can be flattened based on a uniqueness condition.
- Throws:
StandardException
- Thrown on error
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updateTargetLockMode
int updateTargetLockMode()Get the lock mode for the target of an update statement (a delete or update). The update mode will always be row for CurrentOfNodes. It will be table if there is no where clause.- Overrides:
updateTargetLockMode
in classResultSetNode
- Returns:
- The lock mode
- See Also:
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returnsAtMostOneRow
boolean returnsAtMostOneRow()Return whether or not this ResultSet tree is guaranteed to return at most 1 row based on heuristics. (A RowResultSetNode and a SELECT with a non-grouped aggregate will return at most 1 row.)- Overrides:
returnsAtMostOneRow
in classResultSetNode
- Returns:
- Whether or not this ResultSet tree is guaranteed to return at most 1 row based on heuristics.
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referencesSessionSchema
Return true if the node references SESSION schema tables (temporary or permanent)- Overrides:
referencesSessionSchema
in classQueryTreeNode
- Returns:
- true if references SESSION schema tables, else false
- Throws:
StandardException
- Thrown on error
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acceptChildren
Accept the visitor for all visitable children of this node.- Overrides:
acceptChildren
in classResultSetNode
- Parameters:
v
- the visitor- Throws:
StandardException
- on error
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hasAggregatesInSelectList
boolean hasAggregatesInSelectList()- Returns:
- true if there are aggregates in the select list.
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hasWindows
boolean hasWindows()Used by SubqueryNode to avoid flattening of a subquery if a window is defined on it. Note that any inline window definitions should have been collected from both the selectList and orderByList at the time this method is called, so the windows list is complete. This is true after preprocess is completed.- Returns:
- true if this select node has any windows on it
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checkNoWindowFunctions
static void checkNoWindowFunctions(QueryTreeNode clause, String clauseName) throws StandardException - Throws:
StandardException
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replaceOrForbidDefaults
void replaceOrForbidDefaults(TableDescriptor ttd, ResultColumnList tcl, boolean allowDefaults) throws StandardException Replace any DEFAULTs with the associated tree for the default if allowed, or flag (when inside top level set operator nodes). Subqueries are checked for illegal DEFAULTs elsewhere. A no-op for SelectNode.- Overrides:
replaceOrForbidDefaults
in classResultSetNode
- Parameters:
ttd
- The TableDescriptor for the target table.tcl
- The RCL for the target table.allowDefaults
- true if allowed- Throws:
StandardException
- Thrown on error
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hasOffsetFetchFirst
boolean hasOffsetFetchFirst()
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