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

java.lang.Object
  org.apache.derby.impl.sql.compile.QueryTreeNode
      org.apache.derby.impl.sql.compile.QueryTreeNodeVector
          org.apache.derby.impl.sql.compile.FromList

All Implemented Interfaces:

org.apache.derby.iapi.sql.compile.OptimizableList, org.apache.derby.iapi.sql.compile.Visitable

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public class FromList

extends QueryTreeNodeVector

implements org.apache.derby.iapi.sql.compile.OptimizableList

A FromList represents the list of tables in a FROM clause in a DML statement. It extends QueryTreeNodeVector.

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Field Summary
(package private)  boolean	fixedJoinOrder
(package private)  java.util.Properties	properties
(package private)  boolean	useStatistics

 

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

FromList()

 

Method Summary
org.apache.derby.iapi.sql.compile.Visitable	accept(org.apache.derby.iapi.sql.compile.Visitor v)           Accept a visitor, and call v.visit() on child nodes as necessary.
void	addElement(QueryTreeNode qt)
void	addFromTable(FromTable fromTable)           Add a table to the FROM list.
ResultColumn	bindColumnReference(ColumnReference columnReference)           Bind a column reference to one of the tables in this FromList.
void	bindExpressions()           Bind the expressions in this FromList.
void	bindResultColumns(FromList fromListParam)           Bind the result columns of the ResultSetNodes in this FromList when there is no base table to bind them to.
void	bindTables(org.apache.derby.iapi.sql.dictionary.DataDictionary dataDictionary, FromList fromListParam)           Bind the tables in this FromList.
void	bindUntypedNullsToResultColumns(ResultColumnList bindingRCL)           Bind any untyped null nodes to the types in the given ResultColumnList.
(package private)  void	decrementLevel(int decrement)           Decrement (query block) level (0-based) for all of the tables in this from list.
void	destructiveAppend(QueryTreeNodeVector qtnv)
QueryTreeNode	elementAt(int index)
ResultColumnList	expandAll(TableName allTableName)           Expand a "*" into the appropriate ResultColumnList.
void	flattenFromTables(ResultColumnList rcl, PredicateList predicateList, SubqueryList sql, GroupByList gbl)           Flatten all the FromTables that are flattenable.
(package private)  void	genExistsBaseTables(org.apache.derby.iapi.util.JBitSet referencedTableMap, FromList outerFromList, boolean isNotExists)           Mark all of the FromBaseTables in the list as EXISTS FBTs.
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.
FromTable	getFromTableByResultColumn(ResultColumn rc)           Get the FromTable from this list which has the specified ResultColumn in its RCL.
org.apache.derby.iapi.sql.compile.Optimizable	getOptimizable(int index)           Return the nth Optimizable in the list.
(package private)  int[]	getTableNumbers()
(package private)  boolean	hashJoinSpecified()           Return whether or not the user specified a hash join for any of the tables in this list.
boolean	hasOuterJoins()           Returns true if any Outer joins present.
(package private)  int	indexOf(QueryTreeNode qt)
void	init(java.lang.Object optimizeJoinOrder)           Initializer for a FromList
void	init(java.lang.Object optimizeJoinOrder, java.lang.Object fromTable)           Initializer for a FromList
void	initAccessPaths(org.apache.derby.iapi.sql.compile.Optimizer optimizer)           Init the access paths for these optimizables.
(package private)  void	insertElementAt(QueryTreeNode qt, int index)
boolean	legalJoinOrder(int numTablesInQuery)           Tell whether the join order is legal.
boolean	LOJ_reorderable(int numTables)
(package private)  void	markStatementResultSet()           Move the mark for result set being the statement's outermost result set down into the first table of the from list.
void	nondestructiveAppend(QueryTreeNodeVector qtnv)
boolean	optimizeJoinOrder()           Tell whether the join order should be optimized.
void	preprocess(int numTables, GroupByList gbl, ValueNode predicateTree)           Preprocess the query tree - this currently means: o Generating a referenced table map for each ResultSetNode.
void	printSubNodes(int depth)           Prints the sub-nodes of this object.
(package private)  void	pushPredicates(PredicateList predicateList)           Categorize and push the predicates that are pushable.
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) all ? parameters directly under the ResultColumns.
(package private)  java.lang.Object	remove(int index)
(package private)  void	removeAllElements()
(package private)  void	removeElement(QueryTreeNode qt)
(package private)  void	removeElementAt(int index)
void	reOrder(int[] joinOrder)           Set the join order for this list of optimizables.
(package private)  boolean	returnsAtMostSingleRow(ResultColumnList rcl, ValueNode whereClause, PredicateList wherePredicates, org.apache.derby.iapi.sql.dictionary.DataDictionary dd)           This method is used for both subquery flattening and distinct elimination based on a uniqueness condition.
(package private)  void	setElementAt(QueryTreeNode qt, int index)
void	setLevel(int level)           Set the (query block) level (0-based) for the FromTables in this FromList.
void	setOptimizable(int index, org.apache.derby.iapi.sql.compile.Optimizable optimizable)           Set the nth Optimizable to the specified Optimizable.
void	setProperties(java.util.Properties props)           Set the Properties list for this FromList.
int	size()           Return the number of Optimizables in the list.
java.lang.String	toString()           Format this list as a string We can simply iterate through the list.
int	updateTargetLockMode()           Get the lock mode for the target of an update statement (a delete or update).
boolean	useStatistics()           user can specify that s/he doesn't want statistics to be considered when optimizing the query.
void	verifyProperties(org.apache.derby.iapi.sql.dictionary.DataDictionary dDictionary)           Verify that the Properties list with optimizer overrides, if specified, is valid

 

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, makeResultDescription, 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.OptimizableList

size

 

Field Detail

properties

java.util.Properties properties

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fixedJoinOrder

boolean fixedJoinOrder

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useStatistics

boolean useStatistics

Constructor Detail

FromList

public FromList()

Method Detail

init

public void init(java.lang.Object optimizeJoinOrder)

Initializer for a FromList

Overrides:

init in class QueryTreeNode

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init

public void init(java.lang.Object optimizeJoinOrder,
                 java.lang.Object fromTable)
          throws org.apache.derby.iapi.error.StandardException

Initializer for a FromList

Overrides:

init in class QueryTreeNode

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getOptimizable

public org.apache.derby.iapi.sql.compile.Optimizable getOptimizable(int index)

Description copied from interface: org.apache.derby.iapi.sql.compile.OptimizableList

Return the nth Optimizable in the list.

Specified by:

getOptimizable in interface org.apache.derby.iapi.sql.compile.OptimizableList

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setOptimizable

public void setOptimizable(int index,
                           org.apache.derby.iapi.sql.compile.Optimizable optimizable)

Description copied from interface: org.apache.derby.iapi.sql.compile.OptimizableList

Set the nth Optimizable to the specified Optimizable.

Specified by:

setOptimizable in interface org.apache.derby.iapi.sql.compile.OptimizableList

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verifyProperties

public void verifyProperties(org.apache.derby.iapi.sql.dictionary.DataDictionary dDictionary)
                      throws org.apache.derby.iapi.error.StandardException

Description copied from interface: org.apache.derby.iapi.sql.compile.OptimizableList

Verify that the Properties list with optimizer overrides, if specified, is valid

Specified by:

verifyProperties in interface org.apache.derby.iapi.sql.compile.OptimizableList

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addFromTable

public void addFromTable(FromTable fromTable)
                  throws org.apache.derby.iapi.error.StandardException

Add a table to the FROM list.

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referencesTarget

public boolean referencesTarget(java.lang.String name,
                                boolean baseTable)
                         throws org.apache.derby.iapi.error.StandardException

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

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referencesSessionSchema

public boolean referencesSessionSchema()
                                throws org.apache.derby.iapi.error.StandardException

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

Overrides:

referencesSessionSchema in class QueryTreeNode

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getFromTableByName

protected FromTable getFromTableByName(java.lang.String name,
                                       java.lang.String schemaName,
                                       boolean exactMatch)
                                throws org.apache.derby.iapi.error.StandardException

Determine whether or not the specified name is an exposed name in the current query block.

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bindTables

public void bindTables(org.apache.derby.iapi.sql.dictionary.DataDictionary dataDictionary,
                       FromList fromListParam)
                throws org.apache.derby.iapi.error.StandardException

Bind the tables in this FromList. This includes looking them up in the DataDictionary, getting their TableDescriptors and assigning the table numbers.

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bindExpressions

public void bindExpressions()
                     throws org.apache.derby.iapi.error.StandardException

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

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bindResultColumns

public void bindResultColumns(FromList fromListParam)
                       throws org.apache.derby.iapi.error.StandardException

Bind the result columns of the ResultSetNodes in this FromList 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.

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hasOuterJoins

public boolean hasOuterJoins()
                      throws org.apache.derby.iapi.error.StandardException

Returns true if any Outer joins present. Used to set Nullability

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expandAll

public ResultColumnList expandAll(TableName allTableName)
                           throws org.apache.derby.iapi.error.StandardException

Expand a "*" into the appropriate ResultColumnList. If the "*" is unqualified it will expand into a list of all columns in all of the base tables in the from list, otherwise it will expand into a list of all of the columns in the base table that matches the qualification.

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bindColumnReference

public ResultColumn bindColumnReference(ColumnReference columnReference)
                                 throws org.apache.derby.iapi.error.StandardException

Bind a column reference to one of the tables in this FromList. The column name must be unique within the tables in the FromList. An exception is thrown if a column name is not unique. NOTE: Callers are responsible for ordering the FromList by nesting level, with tables at the deepest (current) nesting level first. We will try to match against all FromTables at a given nesting level. If no match is found at a nesting level, then we proceed to the next level. We stop walking the list when the nesting level changes and we have found a match. NOTE: If the ColumnReference is qualified, then we will stop the search at the first nesting level where there is a match on the exposed table name. For example, s (a, b, c), t (d, e, f) select * from s where exists (select * from t s where s.c = a) will not find a match for s.c, which is the expected ANSI behavior. bindTables() must have already been called on this FromList before calling this method.

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rejectParameters

public void rejectParameters()
                      throws org.apache.derby.iapi.error.StandardException

Check for (and reject) all ? parameters directly under the ResultColumns. This is done for SELECT statements.

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LOJ_reorderable

public boolean LOJ_reorderable(int numTables)
                        throws org.apache.derby.iapi.error.StandardException

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preprocess

public void preprocess(int numTables,
                       GroupByList gbl,
                       ValueNode predicateTree)
                throws org.apache.derby.iapi.error.StandardException

Preprocess the query tree - 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 Flatten those FromSubqueries which can be flattened. o Ensuring that a ProjectRestrictNode is generated on top of every FromBaseTable and generated in place of every FromSubquery which could not be flattened. o Pushing single table predicates down to the new ProjectRestrictNodes.

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flattenFromTables

public void flattenFromTables(ResultColumnList rcl,
                              PredicateList predicateList,
                              SubqueryList sql,
                              GroupByList gbl)
                       throws org.apache.derby.iapi.error.StandardException

Flatten all the FromTables that are flattenable. RESOLVE - right now we just flatten FromSubqueries. We should also flatten flattenable JoinNodes here.

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pushPredicates

void pushPredicates(PredicateList predicateList)
              throws org.apache.derby.iapi.error.StandardException

Categorize and push the predicates that are pushable.

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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 QueryTreeNode

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setLevel

public void setLevel(int level)

Set the (query block) level (0-based) for the FromTables in this FromList.

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markStatementResultSet

void markStatementResultSet()

Move the mark for result set being the statement's outermost result set down into the first table of the from list. Generally expect there is only one table at this point.

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getFromTableByResultColumn

public FromTable getFromTableByResultColumn(ResultColumn rc)

Get the FromTable from this list which has the specified ResultColumn in its RCL.

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setProperties

public void setProperties(java.util.Properties props)
                   throws org.apache.derby.iapi.error.StandardException

Set the Properties list for this FromList.

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reOrder

public void reOrder(int[] joinOrder)

Description copied from interface: org.apache.derby.iapi.sql.compile.OptimizableList

Set the join order for this list of optimizables. The join order is represented as an array of integers - each entry in the array stands for the order of the corresponding element in the list. For example, a joinOrder of {2, 0, 1} means that the 3rd Optimizable in the list (element 2, since we are zero-based) is the first one in the join order, followed by the 1st element in the list, and finally by the 2nd element in the list. This method shuffles this OptimizableList to match the join order. Obviously, the size of the array must equal the number of elements in the array, and the values in the array must be between 0 and the number of elements in the array minus 1, and the values in the array must be unique.

Specified by:

reOrder in interface org.apache.derby.iapi.sql.compile.OptimizableList

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useStatistics

public boolean useStatistics()

Description copied from interface: org.apache.derby.iapi.sql.compile.OptimizableList

user can specify that s/he doesn't want statistics to be considered when optimizing the query.

Specified by:

useStatistics in interface org.apache.derby.iapi.sql.compile.OptimizableList

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optimizeJoinOrder

public boolean optimizeJoinOrder()

Description copied from interface: org.apache.derby.iapi.sql.compile.OptimizableList

Tell whether the join order should be optimized.

Specified by:

optimizeJoinOrder in interface org.apache.derby.iapi.sql.compile.OptimizableList

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legalJoinOrder

public boolean legalJoinOrder(int numTablesInQuery)

Description copied from interface: org.apache.derby.iapi.sql.compile.OptimizableList

Tell whether the join order is legal.

Specified by:

legalJoinOrder in interface org.apache.derby.iapi.sql.compile.OptimizableList

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initAccessPaths

public void initAccessPaths(org.apache.derby.iapi.sql.compile.Optimizer optimizer)

Description copied from interface: org.apache.derby.iapi.sql.compile.OptimizableList

Init the access paths for these optimizables.

Specified by:

initAccessPaths in interface org.apache.derby.iapi.sql.compile.OptimizableList

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bindUntypedNullsToResultColumns

public void bindUntypedNullsToResultColumns(ResultColumnList bindingRCL)
                                     throws org.apache.derby.iapi.error.StandardException

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

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decrementLevel

void decrementLevel(int decrement)

Decrement (query block) level (0-based) for all of the tables in this from list. This is useful when flattening a subquery.

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returnsAtMostSingleRow

boolean returnsAtMostSingleRow(ResultColumnList rcl,
                               ValueNode whereClause,
                               PredicateList wherePredicates,
                               org.apache.derby.iapi.sql.dictionary.DataDictionary dd)
                         throws org.apache.derby.iapi.error.StandardException

This method is used for both subquery flattening and distinct elimination based on a uniqueness condition. For subquery flattening we want to make sure that the query block will return at most 1 row. For distinct elimination we want to make sure that the query block will not return any duplicates. 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 columns from the same table is a superset of any unique index on the table) or an EXISTS FBT. In addition, at least 1 of the tables in the list has a set of columns in equality comparisons with expressions that do not include column references from the same query block is a superset of a unique index on that table. (This ensures that the query block will onlyr return a single row.) This method is expected to be called after normalization and after the from list has been preprocessed. It can be called both before and after the predicates have been pulled from the where clause. The algorithm for this is as follows If any table in the query block is not a base table, give up. For each table in the query Ignore exists table since they can only produce one row create a matrix of tables and columns from the table (tableColMap) (this is used to keep track of the join columns and constants that can be used to figure out whether the rows from a join or in a select list are distinct based on unique indexes) create an array of columns from the table(eqOuterCol) (this is used to determine that only one row will be returned from a join) if the current table is the table for the result columns set the result columns in the eqOuterCol and tableColMap (if these columns are a superset of a unique index and all joining tables result in only one row, the results will be distinct) go through all the predicates and update tableColMap and eqOuterCol with join columns and correlation variables, parameters and constants since setting constants, correlation variables and parameters, reduces the number of columns required for uniqueness in a multi-column index, they are set for all the tables (if the table is not the result table, in this case only the column of the result table is set) join columns are just updated for the column in the row of the joining table. check if the marked columns in tableColMap are a superset of a unique index (This means that the join will only produce 1 row when joined with 1 row of another table) check that there is a least one table for which the columns in eqOuterCol(i.e. constant values) are a superset of a unique index (This quarantees that there will be only one row selected from this table). Once all tables have been evaluated, check that all the tables can be joined by unique index or will have only one row

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getTableNumbers

int[] getTableNumbers()

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genExistsBaseTables

void genExistsBaseTables(org.apache.derby.iapi.util.JBitSet referencedTableMap,
                         FromList outerFromList,
                         boolean isNotExists)
                   throws org.apache.derby.iapi.error.StandardException

Mark all of the FromBaseTables in the list as EXISTS FBTs. Each EBT has the same dependency list - those tables that are referenced minus the tables in the from list.

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updateTargetLockMode

public 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.

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hashJoinSpecified

boolean hashJoinSpecified()

Return whether or not the user specified a hash join for any of the tables in this list.

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accept

public org.apache.derby.iapi.sql.compile.Visitable accept(org.apache.derby.iapi.sql.compile.Visitor v)
                                                   throws org.apache.derby.iapi.error.StandardException

Accept a visitor, and call v.visit() on child nodes as necessary.

Specified by:

accept in interface org.apache.derby.iapi.sql.compile.Visitable

Overrides:

accept in class QueryTreeNodeVector

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size

public final int size()

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elementAt

public QueryTreeNode elementAt(int index)

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addElement

public final void addElement(QueryTreeNode qt)

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removeElementAt

final void removeElementAt(int index)

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removeElement

final void removeElement(QueryTreeNode qt)

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remove

final java.lang.Object remove(int index)

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indexOf

final int indexOf(QueryTreeNode qt)

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setElementAt

final void setElementAt(QueryTreeNode qt,
                        int index)

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destructiveAppend

public void destructiveAppend(QueryTreeNodeVector qtnv)

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nondestructiveAppend

public void nondestructiveAppend(QueryTreeNodeVector qtnv)

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removeAllElements

final void removeAllElements()

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insertElementAt

final void insertElementAt(QueryTreeNode qt,
                           int index)

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toString

public java.lang.String toString()

Format this list as a string We can simply iterate through the list. Note each list member is a QueryTreeNode, and so should have its specialization of toString defined.

Overrides:

toString in class QueryTreeNode

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> apache >> derby >> impl >> sql >> [ compile overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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