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:

Node, 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.

Field Summary

Fields

Modifier and Type	Field and Description
private ValueNode	fetchFirst
private boolean	hasJDBClimitClause
private ValueNode	offset
private OrderByList	orderByList
private SchemaDescriptor	origCompilationSchema DERBY-3270: If this subquery represents an expanded view, this holds the current compilation schema at view definition time.
(package private) ResultSetNode	subquery

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

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

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

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

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

AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX

Constructor Summary

Constructors

Constructor and Description
FromSubquery()

Method Summary

Modifier and Type	Method and Description
(package private) void	acceptChildren(Visitor v) Accept the visitor for all visitable children of this node.
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, ValueNode havingClause) 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 orderByList, java.lang.Object offset, java.lang.Object fetchFirst, java.lang.Object hasJDBClimitClause, java.lang.Object correlationName, java.lang.Object derivedRCL, java.lang.Object tableProperties) Intializer for a table in a FROM list.
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) ?
void	setOrigCompilationSchema(SchemaDescriptor sd) Associate this subquery with the original compilation schema of a view.

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

assignCostEstimate, canBeOrdered, considerSortAvoidancePath, convertAbsoluteToRelativeColumnPosition, cursorTargetTable, estimateCost, feasibleJoinStrategy, fillInReferencedTableMap, forUpdate, getBaseTableName, getBestAccessPath, getBestSortAvoidancePath, getCorrelationName, getCostEstimate, getCurrentAccessPath, getFinalCostEstimate, getLevel, getName, getNumColumnsReturned, getOrigTableName, getProperties, getResultColumnsForList, getSchemaDescriptor, getSchemaDescriptor, getScratchCostEstimate, getTableDescriptor, getTableName, getTableNumber, getTrulyTheBestAccessPath, getUserSpecifiedJoinStrategy, hashKeyColumns, hasLargeObjectColumns, hasTableNumber, init, initAccessPaths, initialCapacity, isBaseTable, isCoveringIndex, isFlattenableJoinNode, isJoinColumnForRightOuterJoin, isMaterializable, isOneRowScan, isTargetTable, legalJoinOrder, loadFactor, LOJ_reorderable, markUpdatableByCursor, maxCapacity, memoryUsageOK, modifyAccessPath, needsSpecialRCLBinding, nextAccessPath, optimizeIt, optimizeSubqueries, pullOptPredicates, pushExpressions, pushOptPredicate, rememberAsBest, rememberJoinStrategyAsBest, rememberSortAvoidancePath, resetJoinStrategies, setCostEstimate, setHashKeyColumns, setLevel, setOrigTableName, setProperties, setTableNumber, startOptimizing, supportsMultipleInstantiations, tellRowOrderingAboutConstantColumns, toString, transformOuterJoins, uniqueJoin, updateBestPlanMap, verifyProperties

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

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

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

accept, bindOffsetFetch, bindRowMultiSet, bindUserCatalogType, bindUserType, checkReliability, checkReliability, convertDefaultNode, createTypeDependency, debugFlush, debugPrint, disablePrivilegeCollection, formatNodeString, foundString, generate, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContextManager, getCursorInfo, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getNodeFactory, getNodeType, getNullNode, getParameterTypes, getSchemaDescriptor, getSchemaDescriptor, getStatementType, getTableDescriptor, getTypeCompiler, init, init, init, init, init, init, init, init, init, init, init, init, isAtomic, isInstanceOf, isPrivilegeCollectionRequired, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, makeTableName, nodeHeader, orReliability, parseStatement, printLabel, resolveTableToSynonym, setBeginOffset, setContextManager, setEndOffset, setNodeType, setRefActionInfo, stackPrint, 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

subquery

ResultSetNode subquery

orderByList

private OrderByList orderByList

offset

private ValueNode offset

fetchFirst

private ValueNode fetchFirst

hasJDBClimitClause

private boolean hasJDBClimitClause

origCompilationSchema

private SchemaDescriptor origCompilationSchema

DERBY-3270: If this subquery represents an expanded view, this holds the current compilation schema at view definition time.

Constructor Detail

FromSubquery

public FromSubquery()

Method Detail

init

public void init(java.lang.Object subquery,
                 java.lang.Object orderByList,
                 java.lang.Object offset,
                 java.lang.Object fetchFirst,
                 java.lang.Object hasJDBClimitClause,
                 java.lang.Object correlationName,
                 java.lang.Object derivedRCL,
                 java.lang.Object tableProperties)

Intializer for a table in a FROM list.

Specified by:

init in interface Node

Overrides:

init in class QueryTreeNode

Parameters:

subquery - The subquery

orderByList - ORDER BY list if any, or null

offset - OFFSET if any, or null

fetchFirst - FETCH FIRST if any, or null

hasJDBClimitClause - True if the offset/fetchFirst clauses come from JDBC limit/offset escape syntax

correlationName - The correlation name

derivedRCL - The derived column list

tableProperties - Properties list associated with the table

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

getSubquery

public ResultSetNode getSubquery()

Return the "subquery" from this node.

Returns:

ResultSetNode The "subquery" from this node.

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

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.

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,
                        ValueNode havingClause)
                 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

havingClause - The HAVING clause, 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, or null if allTableName is non-null and doesn't match a table name in this result set

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.

setOrigCompilationSchema

public void setOrigCompilationSchema(SchemaDescriptor sd)

Associate this subquery with the original compilation schema of a view.

Parameters:

sd - schema descriptor of the original compilation schema of the view.

acceptChildren

void acceptChildren(Visitor v)
             throws StandardException

Description copied from class: ResultSetNode

Accept the visitor for all visitable children of this node.

Overrides:

acceptChildren in class ResultSetNode

Parameters:

v - the visitor

Throws:

StandardException - on error

See Also:

QueryTreeNode.acceptChildren(org.apache.derby.iapi.sql.compile.Visitor)