org.apache.derby.impl.sql.compile
Class UnionNode

java.lang.Object
  org.apache.derby.impl.sql.compile.QueryTreeNode
      org.apache.derby.impl.sql.compile.ResultSetNode
          org.apache.derby.impl.sql.compile.FromTable
              org.apache.derby.impl.sql.compile.TableOperatorNode
                  org.apache.derby.impl.sql.compile.UnionNode

All Implemented Interfaces:

Optimizable, Visitable

public class UnionNode

extends TableOperatorNode

A UnionNode represents a UNION in a DML statement. It contains a boolean telling whether the union operation should eliminate duplicate rows.

Author:

Jeff Lichtman

Field Summary

private boolean	addNewNodesCalled
(package private) boolean	all Tells whether to eliminate duplicate rows.
private OrderByList	orderByList
(package private) boolean	tableConstructor
(package private) boolean	topTableConstructor

Fields inherited from class org.apache.derby.impl.sql.compile.TableOperatorNode

leftOptimizer, leftResultSet, nestedInParens, rightOptimizer, rightResultSet

Fields inherited from class org.apache.derby.impl.sql.compile.FromTable

bestAccessPath, bestCostEstimate, bestSortAvoidancePath, correlationName, corrTableName, currentAccessPath, hashKeyColumns, initialCapacity, level, loadFactor, maxCapacity, tableNumber, tableProperties, trulyTheBestAccessPath, userSpecifiedJoinStrategy

Fields inherited from class org.apache.derby.impl.sql.compile.ResultSetNode

costEstimate, cursorTargetTable, insertSource, optimizer, referencedTableMap, resultColumns, resultSetNumber, scratchCostEstimate, statementResultSet

Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode

AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX, beginOffset, endOffset

Constructor Summary

UnionNode()

Method Summary

private ResultSetNode	addNewNodes() Add any new ResultSetNodes that are necessary to the tree.
void	bindExpressions(FromList fromListParam) Bind the expressions under this TableOperatorNode.
void	bindResultColumns(FromList fromListParam) Bind the result columns of this ResultSetNode when there is no base table to bind them to.
void	bindResultColumns(TableDescriptor targetTableDescriptor, FromVTI targetVTI, ResultColumnList targetColumnList, DMLStatementNode statement, FromList fromListParam) Bind the result columns for this ResultSetNode to a base table.
void	bindTargetExpressions(FromList fromListParam) Bind the expressions in the target list.
void	bindUntypedNullsToResultColumns(ResultColumnList rcl) Bind the result columns of a table constructor to the types in the given ResultColumnList.
private void	buildRCL() Build the RCL for this node.
ResultSetNode	enhanceRCLForInsert(int numTargetColumns, int[] colMap, DataDictionary dataDictionary, TableDescriptor targetTD, FromVTI targetVTI) This ResultSet is the source for an Insert.
ResultSetNode	ensurePredicateList(int numTables) Ensure that the top of the RSN tree has a PredicateList.
boolean	flattenableInFromSubquery(FromList fromList) Evaluate whether or not the subquery in a FromSubquery is flattenable.
void	generate(ActivationClassBuilder acb, MethodBuilder mb) Generate the code for this UnionNode.
protected FromTable	getFromTableByName(java.lang.String name, java.lang.String schemaName, boolean exactMatch) Determine whether or not the specified name is an exposed name in the current query block.
(package private) int	getParamColumnTypes(DataTypeDescriptor[] types, RowResultSetNode rrsn) Get the parameter types from the given RowResultSetNode into the given array of types.
void	init(java.lang.Object leftResult, java.lang.Object rightResult, java.lang.Object all, java.lang.Object tableConstructor, java.lang.Object tableProperties) Initializer for a UnionNode.
void	markTopTableConstructor() Mark this as the top node of a table constructor.
Optimizable	modifyAccessPath(JBitSet outerTables) Modify the access path for this Optimizable, as necessary.
ResultSetNode	modifyAccessPaths() Modify the access paths according to the decisions the optimizer made.
CostEstimate	optimizeIt(Optimizer optimizer, OptimizablePredicateList predList, CostEstimate outerCost, RowOrdering rowOrdering) Choose the best access path for this Optimizable.
boolean	performMaterialization(JBitSet outerTables) Return whether or not to materialize this ResultSet tree.
ResultSetNode	preprocess(int numTables, GroupByList gbl, FromList fromList) Put a ProjectRestrictNode on top of each FromTable in the FromList.
(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	rejectParameters() Check for (and reject) ?
(package private) void	setParamColumnTypes(DataTypeDescriptor[] types, RowResultSetNode rrsn) Set the type of each ?
void	setResultToBooleanTrueNode(boolean onlyConvertAlls) Set the result column for the subquery to a boolean true, Useful for transformations such as changing: where exists (select ... from ...)
(package private) void	setTableConstructorTypes(ResultColumnList typeColumns) Set the type of column in the result column lists of each source of this union tree to the type in the given result column list (which represents the result columns for an insert).
(package private) boolean	tableConstructor() Tell whether this is a UNION for a table constructor.
java.lang.String	toString() Convert this object to a String.
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.TableOperatorNode

accept, bindExpressionsWithTables, bindNonVTITables, bindVTITables, decrementLevel, getExposedName, getLeftmostResultSet, getLeftResultSet, getNestedInParens, getRightResultSet, init, markOrderingDependent, needsSpecialRCLBinding, optimize, optimizeSource, printSubNodes, projectResultColumns, referencesSessionSchema, referencesTarget, replaceDefaults, setLeftmostResultSet, setLevel, setNestedInParens, setReferencedColumns, verifyProperties

Methods inherited from class org.apache.derby.impl.sql.compile.FromTable

areAllColumnsProjected, assignCostEstimate, canBeOrdered, considerSortAvoidancePath, convertAbsoluteToRelativeColumnPosition, cursorTargetTable, estimateCost, feasibleJoinStrategy, fillInReferencedTableMap, flatten, forUpdate, getBaseTableName, getBestAccessPath, getBestSortAvoidancePath, getCostEstimate, getCurrentAccessPath, getLevel, getName, getNumColumnsReturned, getProperties, getResultColumnsForList, getSchemaDescriptor, getSchemaDescriptor, getScratchCostEstimate, getTableDescriptor, getTableName, getTableNumber, getTrulyTheBestAccessPath, getUserSpecifiedJoinStrategy, hashKeyColumns, hasTableNumber, init, initAccessPaths, initialCapacity, isBaseTable, isCoveringIndex, isFlattenableJoinNode, isMaterializable, isOneRowScan, isTargetTable, legalJoinOrder, loadFactor, LOJ_reorderable, markUpdatableByCursor, maxCapacity, memoryUsage, nextAccessPath, optimizeSubqueries, pullOptPredicates, pushExpressions, pushOptPredicate, rememberAsBest, rememberJoinStrategyAsBest, rememberSortAvoidancePath, resetJoinStrategies, setAllColumnsProjected, setCostEstimate, setHashKeyColumns, setProperties, setTableNumber, startOptimizing, supportsMultipleInstantiations, tellRowOrderingAboutConstantColumns, transformOuterJoins, uniqueJoin

Methods inherited from class org.apache.derby.impl.sql.compile.ResultSetNode

addNewPredicate, assignResultSetNumber, changeAccessPath, closeMethodArgument, columnTypesAndLengthsMatch, considerMaterialization, generateNormalizationResultSet, generateResultSet, genNewRCForInsert, genNormalizeResultSetNode, genProjectRestrict, genProjectRestrict, genProjectRestrictForReordering, getAllResultColumns, getCostEstimate, getCursorTargetTable, getFinalCostEstimate, getFromList, getMatchingColumn, getNewCostEstimate, getOptimizer, getReferencedTableMap, getResultColumns, getResultSetNumber, isNotExists, isOneRowResultSet, isOrderedOn, isPossibleDistinctScan, isUpdatableCursor, LOJgetReferencedTables, makeResultDescription, makeResultDescriptors, markAsCursorTargetTable, markForDistinctScan, markStatementResultSet, notCursorTargetTable, notFlattenableJoin, numDistinctAggregates, parseDefault, renameGeneratedResultNames, returnsAtMostOneRow, setInsertSource, setReferencedTableMap, setResultColumns, subqueryReferencesTarget, updateTargetLockMode

Methods inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode

bind, convertDefaultNode, debugFlush, debugPrint, executeSchemaName, executeStatementName, formatNodeString, foundString, generate, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContextManager, getCursorInfo, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getNodeFactory, getNodeType, getNullNode, getParameterTypes, getRowEstimate, getSchemaDescriptor, getSchemaDescriptor, getSPSName, getStatementType, getTableDescriptor, getTypeCompiler, init, init, init, init, init, init, init, init, init, init, init, isAtomic, isInstanceOf, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, needsSavepoint, nodeHeader, optimize, parseQueryText, printLabel, setBeginOffset, setContextManager, setEndOffset, setNodeType, setRefActionInfo, treePrint, treePrint, verifyClassExist

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.derby.iapi.sql.compile.Optimizable

getDataDictionary, getReferencedTableMap, getResultSetNumber

Field Detail

all

boolean all

Tells whether to eliminate duplicate rows. all == TRUE means do not eliminate duplicates, all == FALSE means eliminate duplicates.

tableConstructor

boolean tableConstructor

topTableConstructor

boolean topTableConstructor

addNewNodesCalled

private boolean addNewNodesCalled

orderByList

private OrderByList orderByList

Constructor Detail

UnionNode

public UnionNode()

Method Detail

init

public void init(java.lang.Object leftResult,
                 java.lang.Object rightResult,
                 java.lang.Object all,
                 java.lang.Object tableConstructor,
                 java.lang.Object tableProperties)
          throws StandardException

Initializer for a UnionNode.

Overrides:

init in class QueryTreeNode

Parameters:

leftResult - The ResultSetNode on the left side of this union

rightResult - The ResultSetNode on the right side of this union

all - Whether or not this is a UNION ALL.

tableConstructor - Whether or not this is from a table constructor.

tableProperties - Properties list associated with the table

Throws:

StandardException - Thrown on error

markTopTableConstructor

public void markTopTableConstructor()

Mark this as the top node of a table constructor.

tableConstructor

boolean tableConstructor()

Tell whether this is a UNION for a table constructor.

rejectParameters

public void rejectParameters()
                      throws StandardException

Check for (and reject) ? parameters directly under the ResultColumns. This is done for SELECT statements. Don't reject parameters that are in a table constructor - these are allowed, as long as the table constructor is in an INSERT statement or each column of the table constructor has at least one non-? column. The latter case is checked below, in bindExpressions().

Overrides:

rejectParameters in class TableOperatorNode

Returns:

Nothing

Throws:

StandardException - Thrown if a ? parameter found directly under a ResultColumn

setTableConstructorTypes

void setTableConstructorTypes(ResultColumnList typeColumns)
                        throws StandardException

Set the type of column in the result column lists of each source of this union tree to the type in the given result column list (which represents the result columns for an insert). This is only for table constructors that appear in insert statements.

Overrides:

setTableConstructorTypes in class ResultSetNode

Parameters:

typeColumns - The ResultColumnList containing the desired result types.

Throws:

StandardException - Thrown on error

optimizeIt

public CostEstimate optimizeIt(Optimizer optimizer,
                               OptimizablePredicateList predList,
                               CostEstimate outerCost,
                               RowOrdering rowOrdering)
                        throws StandardException

Description copied from interface: Optimizable

Choose the best access path for this Optimizable.

Specified by:

optimizeIt in interface Optimizable

Overrides:

optimizeIt in class FromTable

Throws:

StandardException - Thrown on error

See Also:

Optimizable.optimizeIt(org.apache.derby.iapi.sql.compile.Optimizer, org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.sql.compile.CostEstimate, org.apache.derby.iapi.sql.compile.RowOrdering)

modifyAccessPath

public Optimizable modifyAccessPath(JBitSet outerTables)
                             throws StandardException

Description copied from interface: Optimizable

Modify the access path for this Optimizable, as necessary. This includes things like adding a result set to translate from index rows to base rows

Specified by:

modifyAccessPath in interface Optimizable

Overrides:

modifyAccessPath in class TableOperatorNode

Throws:

StandardException - Thrown on error

See Also:

Optimizable.modifyAccessPath(org.apache.derby.iapi.util.JBitSet)

modifyAccessPaths

public ResultSetNode modifyAccessPaths()
                                throws StandardException

Description copied from class: ResultSetNode

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 class TableOperatorNode

Throws:

StandardException - Thrown on error

See Also:

ResultSetNode.modifyAccessPaths()

addNewNodes

private ResultSetNode addNewNodes()
                           throws StandardException

Add any new ResultSetNodes that are necessary to the tree. We wait until after optimization to do this in order to make it easier on the optimizer.

Returns:

(Potentially new) head of the ResultSetNode tree.

Throws:

StandardException - Thrown on error

toString

public java.lang.String toString()

Convert this object to a String. See comments in QueryTreeNode.java for how this should be done for tree printing.

Overrides:

toString in class TableOperatorNode

Returns:

This object as a String

bindExpressions

public void bindExpressions(FromList fromListParam)
                     throws StandardException

Bind the expressions under this TableOperatorNode. This means binding the sub-expressions, as well as figuring out what the return type is for each expression.

Overrides:

bindExpressions in class TableOperatorNode

Returns:

Nothing

Throws:

StandardException - Thrown on error

bindResultColumns

public void bindResultColumns(FromList fromListParam)
                       throws StandardException

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 class TableOperatorNode

Parameters:

fromListParam - FromList to use/append to.

Returns:

Nothing

Throws:

StandardException - Thrown on error

bindResultColumns

public 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 class TableOperatorNode

Parameters:

targetTableDescriptor - The TableDescriptor for the table being updated or inserted into

targetColumnList - 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.

Returns:

Nothing

Throws:

StandardException - Thrown on error

buildRCL

private void buildRCL()
               throws StandardException

Build the RCL for this node. We propagate the RCL up from the left child to form this node's RCL.

Returns:

Nothing

Throws:

StandardException - Thrown on error

bindUntypedNullsToResultColumns

public void bindUntypedNullsToResultColumns(ResultColumnList rcl)
                                     throws StandardException

Bind the result columns of a table constructor to the types in the given ResultColumnList. Use when inserting from a table constructor, and there are nulls in the values clauses.

Overrides:

bindUntypedNullsToResultColumns in class ResultSetNode

Parameters:

rcl - The ResultColumnList with the types to bind to

Throws:

StandardException - Thrown on error.

getParamColumnTypes

int getParamColumnTypes(DataTypeDescriptor[] types,
                        RowResultSetNode rrsn)

Get the parameter types from the given RowResultSetNode into the given array of types. If an array position is already filled in, don't clobber it.

Parameters:

types - The array of types to fill in

rrsn - The RowResultSetNode from which to take the param types

Returns:

The number of new types found in the RowResultSetNode

setParamColumnTypes

void setParamColumnTypes(DataTypeDescriptor[] types,
                         RowResultSetNode rrsn)
                   throws StandardException

Set the type of each ? parameter in the given RowResultSetNode according to its ordinal position in the given array of types.

Parameters:

types - An array of types containing the proper type for each ? parameter, by ordinal position.

rrsn - A RowResultSetNode that could contain ? parameters whose types need to be set.

Throws:

StandardException - Thrown on error

bindTargetExpressions

public void bindTargetExpressions(FromList fromListParam)
                           throws StandardException

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 class ResultSetNode

Returns:

Nothing

Throws:

StandardException - Thrown on error

pushOrderByList

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.

Overrides:

pushOrderByList in class ResultSetNode

Parameters:

orderByList - The order by list

Returns:

Nothing.

preprocess

public ResultSetNode preprocess(int numTables,
                                GroupByList gbl,
                                FromList fromList)
                         throws StandardException

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 class TableOperatorNode

Parameters:

numTables - Number of tables in the DML Statement

gbl - The group by list, if any

fromList - The from list, if any

Returns:

The generated ProjectRestrictNode atop the original FromTable.

Throws:

StandardException - Thrown on error

ensurePredicateList

public ResultSetNode ensurePredicateList(int numTables)
                                  throws StandardException

Ensure that the top of the RSN tree has a PredicateList.

Overrides:

ensurePredicateList in class ResultSetNode

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

verifySelectStarSubquery

public void verifySelectStarSubquery(FromList outerFromList,
                                     int subqueryType)
                              throws StandardException

Verify that a SELECT * is valid for this type of subquery.

Overrides:

verifySelectStarSubquery in class ResultSetNode

Parameters:

outerFromList - The FromList from the outer query block(s)

subqueryType - The subquery type

Returns:

None

Throws:

StandardException - Thrown on error

getFromTableByName

protected FromTable getFromTableByName(java.lang.String name,
                                       java.lang.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 class TableOperatorNode

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

setResultToBooleanTrueNode

public void setResultToBooleanTrueNode(boolean onlyConvertAlls)
                                throws StandardException

Set the result column for the subquery to a boolean true, Useful for transformations such as changing: where exists (select ... from ...) to: where (select true from ...) NOTE: No transformation is performed if the ResultColumn.expression is already the correct boolean constant.

Overrides:

setResultToBooleanTrueNode in class ResultSetNode

Parameters:

onlyConvertAlls - Boolean, whether or not to just convert *'s

Returns:

Nothing.

Throws:

StandardException - Thrown on error

enhanceRCLForInsert

public ResultSetNode enhanceRCLForInsert(int numTargetColumns,
                                         int[] colMap,
                                         DataDictionary dataDictionary,
                                         TableDescriptor targetTD,
                                         FromVTI targetVTI)
                                  throws StandardException

This ResultSet is the source for an Insert. The target RCL is in a different order and/or a superset of this RCL. In most cases we will reorder and/or add defaults to the current RCL so that is matches the target RCL. Those RSNs whose generate() method does not handle projects will insert a PRN, with a new RCL which matches the target RCL, above the current RSN. NOTE - The new or enhanced RCL will be fully bound.

Overrides:

enhanceRCLForInsert in class ResultSetNode

Parameters:

numTargetColumns - # of columns in target RCL

dataDictionary - DataDictionary to use

targetTD - TableDescriptor for target if the target is not a VTI, null if a VTI

targetVTI - Target description if it is a VTI, null if not a VTI

Returns:

ResultSetNode The new top of the tree

Throws:

StandardException - Thrown on error

flattenableInFromSubquery

public boolean flattenableInFromSubquery(FromList fromList)

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 no top level subqueries. (RESOLVE - we can relax this) o It does not contain a group by or having clause o It does not contain aggregates.

Overrides:

flattenableInFromSubquery in class ResultSetNode

Parameters:

fromList - The outer from list

Returns:

boolean Whether or not the FromSubquery is flattenable.

performMaterialization

public boolean performMaterialization(JBitSet outerTables)
                               throws StandardException

Return whether or not to materialize this ResultSet tree.

Overrides:

performMaterialization in class ResultSetNode

Returns:

Whether or not to materialize this ResultSet tree. would return valid results.

Throws:

StandardException - Thrown on error

generate

public void generate(ActivationClassBuilder acb,
                     MethodBuilder mb)
              throws StandardException

Generate the code for this UnionNode.

Overrides:

generate in class QueryTreeNode

Parameters:

acb - The ActivationClassBuilder for the class being built

mb - The method for the generated code to go into

Throws:

StandardException - Thrown on error