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

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.FromSubquery

All Implemented Interfaces:

Optimizable, Visitable

public class FromSubquery

extends FromTable

A FromSubquery represents a subquery in the FROM list of a DML statement. The current implementation of this class is only sufficient for Insert's need to push a new select on top of the one the user specified, to make the selected structure match that of the insert target table.

Author:

Jeff Lichtman

Field Summary

(package private) boolean	generatedForGroupByClause
(package private) boolean	generatedForHavingClause
(package private) ResultSetNode	subquery

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

FromSubquery()

Method Summary

void	bindExpressions(FromList fromListParam) Bind the expressions in this FromSubquery.
ResultSetNode	bindNonVTITables(DataDictionary dataDictionary, FromList fromListParam) Bind this subquery that appears in the FROM list.
void	bindUntypedNullsToResultColumns(ResultColumnList bindingRCL) Bind any untyped null nodes to the types in the given ResultColumnList.
ResultSetNode	bindVTITables(FromList fromListParam) Bind this subquery that appears in the FROM list.
(package private) void	decrementLevel(int decrement) Decrement (query block) level (0-based) for this FromTable.
ResultSetNode	extractSubquery(int numTables) Extract out and return the subquery, with a PRN on top.
FromList	flatten(ResultColumnList rcl, PredicateList outerPList, SubqueryList sql, GroupByList gbl) Flatten this FSqry into the outer query block.
ResultColumnList	getAllResultColumns(TableName allTableName) Expand a "*" into a ResultColumnList with all of the result columns from the subquery.
java.lang.String	getExposedName() Get the exposed name for this table, which is the name that can be used to refer to it in the rest of the query.
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.
ResultColumn	getMatchingColumn(ColumnReference columnReference) Try to find a ResultColumn in the table represented by this FromBaseTable that matches the name in the given ColumnReference.
ResultSetNode	getSubquery() Return the "subquery" from this node.
void	init(java.lang.Object subquery, java.lang.Object correlationName, java.lang.Object derivedRCL, java.lang.Object tableProperties) Intializer for a table in a FROM list.
void	markAsForGroupByClause() Mark this FromSubquery as being generated for a GROUP BY clause.
void	markAsForHavingClause() Mark this FromSubquery as being generated for a HAVING clause.
ResultSetNode	preprocess(int numTables, GroupByList gbl, FromList fromList) Preprocess a ResultSetNode - this currently means: o Generating a referenced table map for each ResultSetNode.
void	printSubNodes(int depth) Prints the sub-nodes of this object.
boolean	referencesSessionSchema() Return true if the node references SESSION schema tables (temporary or permanent)
boolean	referencesTarget(java.lang.String name, boolean baseTable) Search to see if a query references the specifed table name.
void	rejectParameters() Check for (and reject) ?
java.lang.String	toString() Convert this object to a String.

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

areAllColumnsProjected, assignCostEstimate, canBeOrdered, considerSortAvoidancePath, convertAbsoluteToRelativeColumnPosition, cursorTargetTable, estimateCost, feasibleJoinStrategy, fillInReferencedTableMap, 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, memoryUsageOK, modifyAccessPath, needsSpecialRCLBinding, nextAccessPath, optimizeIt, optimizeSubqueries, pullOptPredicates, pushExpressions, pushOptPredicate, rememberAsBest, rememberJoinStrategyAsBest, rememberSortAvoidancePath, resetJoinStrategies, setAllColumnsProjected, setCostEstimate, setHashKeyColumns, setLevel, setProperties, setTableNumber, startOptimizing, supportsMultipleInstantiations, tellRowOrderingAboutConstantColumns, transformOuterJoins, uniqueJoin, verifyProperties

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

accept, addNewPredicate, assignResultSetNumber, bindExpressionsWithTables, bindResultColumns, bindResultColumns, bindTargetExpressions, changeAccessPath, closeMethodArgument, columnTypesAndLengthsMatch, considerMaterialization, enhanceRCLForInsert, ensurePredicateList, flattenableInFromSubquery, generateNormalizationResultSet, generateResultSet, genNewRCForInsert, genNormalizeResultSetNode, genProjectRestrict, genProjectRestrict, genProjectRestrictForReordering, getCostEstimate, getCursorTargetTable, getFinalCostEstimate, getFromList, getNewCostEstimate, getOptimizer, getReferencedTableMap, getResultColumns, getResultSetNumber, isNotExists, isOneRowResultSet, isOrderedOn, isPossibleDistinctScan, isUpdatableCursor, LOJgetReferencedTables, makeResultDescription, makeResultDescriptors, markAsCursorTargetTable, markForDistinctScan, markOrderingDependent, markStatementResultSet, modifyAccessPaths, notCursorTargetTable, notFlattenableJoin, numDistinctAggregates, optimize, parseDefault, performMaterialization, projectResultColumns, pushOrderByList, rejectXMLValues, renameGeneratedResultNames, replaceDefaults, returnsAtMostOneRow, setInsertSource, setReferencedTableMap, setResultColumns, setResultToBooleanTrueNode, setTableConstructorTypes, subqueryReferencesTarget, updateTargetLockMode, verifySelectStarSubquery

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

bind, convertDefaultNode, debugFlush, debugPrint, executeSchemaName, executeStatementName, formatNodeString, foundString, generate, 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, init, isAtomic, isInstanceOf, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, needsSavepoint, nodeHeader, optimize, parseQueryText, printLabel, resolveTableToSynonym, 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

generatedForGroupByClause

boolean generatedForGroupByClause

generatedForHavingClause

boolean generatedForHavingClause

subquery

ResultSetNode subquery

Constructor Detail

FromSubquery

public FromSubquery()

Method Detail

init

public void init(java.lang.Object subquery,
                 java.lang.Object correlationName,
                 java.lang.Object derivedRCL,
                 java.lang.Object tableProperties)

Intializer for a table in a FROM list.

Overrides:

init in class QueryTreeNode

Parameters:

correlationName - The correlation name

derivedRCL - The derived column list

tableProperties - Properties list associated with the table

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 FromTable

Returns:

This object as a String

printSubNodes

public 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 class ResultSetNode

Parameters:

depth - The depth of this node in the tree

Returns:

Nothing

getSubquery

public ResultSetNode getSubquery()

Return the "subquery" from this node.

Returns:

ResultSetNode The "subquery" from this node.

markAsForGroupByClause

public void markAsForGroupByClause()

Mark this FromSubquery as being generated for a GROUP BY clause. (This node represents the SELECT thru GROUP BY clauses. We appear in the FromList of a SelectNode generated to represent the result of the GROUP BY. This allows us to add ResultColumns to the SelectNode for the user's query.

Returns:

Nothing.

markAsForHavingClause

public void markAsForHavingClause()

Mark this FromSubquery as being generated for a HAVING clause. (This node represents the SELECT thru GROUP BY clauses. We appear in the FromList of a SelectNode generated to represent the actual HAVING clause.

Returns:

Nothing.

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 FromTable

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

bindNonVTITables

public ResultSetNode bindNonVTITables(DataDictionary dataDictionary,
                                      FromList fromListParam)
                               throws StandardException

Bind this subquery that appears in the FROM list.

Overrides:

bindNonVTITables in class ResultSetNode

Parameters:

dataDictionary - The DataDictionary to use for binding

fromListParam - FromList to use/append to.

Returns:

ResultSetNode The bound FromSubquery.

Throws:

StandardException - Thrown on error

bindVTITables

public ResultSetNode bindVTITables(FromList fromListParam)
                            throws StandardException

Bind this subquery that appears in the FROM list.

Overrides:

bindVTITables in class ResultSetNode

Parameters:

fromListParam - FromList to use/append to.

Returns:

ResultSetNode The bound FromSubquery.

Throws:

StandardException - Thrown on error

rejectParameters

public void rejectParameters()
                      throws StandardException

Check for (and reject) ? parameters directly under the ResultColumns. This is done for SELECT statements. For FromSubquery, we simply pass the check through to the subquery.

Overrides:

rejectParameters in class ResultSetNode

Returns:

Nothing

Throws:

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

bindExpressions

public void bindExpressions(FromList fromListParam)
                     throws StandardException

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

Overrides:

bindExpressions in class ResultSetNode

Parameters:

fromListParam - FromList to use/append to.

Returns:

Nothing

Throws:

StandardException - Thrown on error

getMatchingColumn

public ResultColumn getMatchingColumn(ColumnReference columnReference)
                               throws StandardException

Try to find a ResultColumn in the table represented by this FromBaseTable that matches the name in the given ColumnReference.

Overrides:

getMatchingColumn in class ResultSetNode

Parameters:

columnReference - The columnReference whose name we're looking for in the given table.

Returns:

A ResultColumn whose expression is the ColumnNode that matches the ColumnReference. Returns null if there is no match.

Throws:

StandardException - Thrown on error

preprocess

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

Preprocess a ResultSetNode - this currently means: o Generating a referenced table map for each ResultSetNode. o Putting the WHERE and HAVING clauses in conjunctive normal form (CNF). o Converting the WHERE and HAVING clauses into PredicateLists and classifying them. o Ensuring that a ProjectRestrictNode is generated on top of every FromBaseTable and generated in place of every FromSubquery. o Pushing single table predicates down to the new ProjectRestrictNodes.

Overrides:

preprocess in class ResultSetNode

Parameters:

numTables - The number of tables in the DML Statement

gbl - The group by list, if any

fromList - The from list, if any

Returns:

ResultSetNode at top of preprocessed tree.

Throws:

StandardException - Thrown on error

extractSubquery

public ResultSetNode extractSubquery(int numTables)
                              throws StandardException

Extract out and return the subquery, with a PRN on top. (See FromSubquery.preprocess() for more details.)

Parameters:

numTables - The number of tables in the DML Statement

Returns:

ResultSetNode at top of extracted tree.

Throws:

StandardException - Thrown on error

flatten

public FromList flatten(ResultColumnList rcl,
                        PredicateList outerPList,
                        SubqueryList sql,
                        GroupByList gbl)
                 throws StandardException

Flatten this FSqry into the outer query block. The steps in flattening are: o Mark all ResultColumns as redundant, so that they are "skipped over" at generate(). o Append the wherePredicates to the outer list. o Return the fromList so that the caller will merge the 2 lists RESOLVE - FSqrys with subqueries are currently not flattenable. Some of them can be flattened, however. We need to merge the subquery list when we relax this restriction. NOTE: This method returns NULL when flattening RowResultSetNodes (the node for a VALUES clause). The reason is that no reference is left to the RowResultSetNode after flattening is done - the expressions point directly to the ValueNodes in the RowResultSetNode's ResultColumnList.

Overrides:

flatten in class FromTable

Parameters:

rcl - The RCL from the outer query

outerPList - PredicateList to append wherePredicates to.

sql - The SubqueryList from the outer query

gbl - The group by list, if any

Returns:

FromList The fromList from the underlying SelectNode.

Throws:

StandardException - Thrown on error

getExposedName

public java.lang.String getExposedName()

Get the exposed name for this table, which is the name that can be used to refer to it in the rest of the query.

Overrides:

getExposedName in class FromTable

Returns:

The exposed name for this table.

getAllResultColumns

public ResultColumnList getAllResultColumns(TableName allTableName)
                                     throws StandardException

Expand a "*" into a ResultColumnList with all of the result columns from the subquery.

Overrides:

getAllResultColumns in class ResultSetNode

Parameters:

allTableName - The qualifier on the "*"

Returns:

ResultColumnList The expanded list

Throws:

StandardException - Thrown on error

referencesTarget

public boolean referencesTarget(java.lang.String name,
                                boolean baseTable)
                         throws StandardException

Search to see if a query references the specifed table name.

Overrides:

referencesTarget in class ResultSetNode

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

referencesSessionSchema

public boolean referencesSessionSchema()
                                throws StandardException

Return true if the node references SESSION schema tables (temporary or permanent)

Overrides:

referencesSessionSchema in class QueryTreeNode

Returns:

true if references SESSION schema tables, else false

Throws:

StandardException - Thrown on error

bindUntypedNullsToResultColumns

public void bindUntypedNullsToResultColumns(ResultColumnList bindingRCL)
                                     throws StandardException

Bind any untyped null nodes to the types in the given ResultColumnList.

Overrides:

bindUntypedNullsToResultColumns in class ResultSetNode

Parameters:

bindingRCL - The ResultColumnList with the types to bind to.

Throws:

StandardException - Thrown on error

decrementLevel

void decrementLevel(int decrement)

Decrement (query block) level (0-based) for this FromTable. This is useful when flattening a subquery.

Overrides:

decrementLevel in class FromTable

Parameters:

decrement - The amount to decrement by.