org.apache.derby.impl.sql.compile

Class BinaryComparisonOperatorNode

java.lang.Object

org.apache.derby.impl.sql.compile.QueryTreeNode

org.apache.derby.impl.sql.compile.ValueNode

org.apache.derby.impl.sql.compile.OperatorNode

org.apache.derby.impl.sql.compile.BinaryOperatorNode

org.apache.derby.impl.sql.compile.BinaryComparisonOperatorNode

All Implemented Interfaces:

Node, Visitable

Direct Known Subclasses:

BinaryRelationalOperatorNode

public abstract class BinaryComparisonOperatorNode
extends BinaryOperatorNode

This node is the superclass for all binary comparison operators, such as =, <>, <, etc.

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	betweenSelectivity
private boolean	forQueryRewrite

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

AND, BinaryArgTypes, BinaryMethodNames, BinaryOperators, BinaryResultTypes, CONCATENATE, DIVIDE, EQ, GE, GT, LE, leftInterfaceType, leftOperand, LIKE, LT, methodName, MINUS, NE, operator, operatorType, OR, PLUS, receiver, resultInterfaceType, rightInterfaceType, rightOperand, TIMES, XMLEXISTS_OP, XMLQUERY_OP

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

transformed

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
BinaryComparisonOperatorNode()

Method Summary

Methods

Modifier and Type	Method and Description
void	bindComparisonOperator() Test the type compatability of the operands and set the type info for this node.
ValueNode	bindExpression(FromList fromList, SubqueryList subqueryList, java.util.List aggregateVector) Bind this comparison operator.
ValueNode	changeToCNF(boolean underTopAndNode) Finish putting an expression into conjunctive normal form.
(package private) ValueNode	eliminateNots(boolean underNotNode) Eliminate NotNodes in the current query block.
ValueNode	genSQLJavaSQLTree() generate a SQL->Java->SQL conversion tree above the left and right operand of this Binary Operator Node if needed.
(package private) boolean	getBetweenSelectivity() Return whether or not to use the between selectivity for this node.
boolean	getForQueryRewrite() Was this node generated in a query rewrite?
(package private) abstract BinaryOperatorNode	getNegation(ValueNode leftOperand, ValueNode rightOperand) Negate the comparison.
(package private) abstract BinaryOperatorNode	getSwappedEquivalent() Return a node equivalent to this node, but with the left and right operands swapped.
void	init(java.lang.Object leftOperand, java.lang.Object rightOperand, java.lang.Object operator, java.lang.Object methodName, java.lang.Object forQueryRewrite) Initializer for a BinaryComparisonOperatorNode
ValueNode	preprocess(int numTables, FromList outerFromList, SubqueryList outerSubqueryList, PredicateList outerPredicateList) Preprocess an expression tree.
(package private) void	setBetweenSelectivity() Use between selectivity when calculating the selectivity.
void	setForQueryRewrite(boolean val) This node was generated as part of a query rewrite.

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

acceptChildren, bindXMLQuery, categorize, constantExpression, generateExpression, getLeftOperand, getOrderableVariantType, getReceiverInterfaceName, getRightOperand, init, init, init, isConstantExpression, isEquivalent, printSubNodes, remapColumnReferencesToExpressions, setLeftOperand, setLeftRightInterfaceType, setMethodName, setOperator, setRightOperand, toString

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

pushSqlXmlUtil

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

bindExpression, checkIsBoolean, checkTopPredicatesForEqualsConditions, copyFields, evaluateConstantExpressions, genEqualsFalseTree, generate, generateFilter, genIsNullTree, getClone, getColumnName, getConstantValueAsObject, getDataValueFactory, getSchemaName, getSourceResultColumn, getTableName, getTablesReferenced, getTransformed, getTypeCompiler, getTypeId, getTypeServices, isBinaryEqualsOperatorNode, isBooleanFalse, isBooleanTrue, isCloneable, isInListProbeNode, isParameterNode, isRelationalOperator, isSameNodeType, optimizableEqualityNode, putAndsOnTop, requiresTypeFromContext, selectivity, setCollationInfo, setCollationInfo, setCollationUsingCompilationSchema, setCollationUsingCompilationSchema, setNullability, setTransformed, setType, setType, setType, updatableByCursor, verifyChangeToCNF, verifyEliminateNots, verifyPutAndsOnTop

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, 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, isAtomic, isInstanceOf, isPrivilegeCollectionRequired, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, makeTableName, nodeHeader, orReliability, parseStatement, printLabel, referencesSessionSchema, 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

Field Detail

forQueryRewrite

private boolean forQueryRewrite

betweenSelectivity

private boolean betweenSelectivity

Constructor Detail

BinaryComparisonOperatorNode

public BinaryComparisonOperatorNode()

Method Detail

init

public void init(java.lang.Object leftOperand,
        java.lang.Object rightOperand,
        java.lang.Object operator,
        java.lang.Object methodName,
        java.lang.Object forQueryRewrite)

Initializer for a BinaryComparisonOperatorNode

Specified by:

init in interface Node

Overrides:

init in class ValueNode

Parameters:

leftOperand - The left operand of the comparison

rightOperand - The right operand of the comparison

operator - The name of the operator

methodName - The name of the method to call in the generated class

forQueryRewrite - Can be true only if if this node has been added by an internal rewrite of the query. This allows binding to be more liberal when checking it against allowed syntax. This parameter will be passed FALSE when a new instance of the node is being created(which is the majority of the cases). But when an existing node is getting cloned, the value of this parameter should be passed as the originalNode.getForQueryRewrite(). Examples of this can be found in Predicate.Java and PredicateList.java

setForQueryRewrite

public void setForQueryRewrite(boolean val)

This node was generated as part of a query rewrite. Bypass the normal comparability checks.

Parameters:

val - true if this was for a query rewrite

getForQueryRewrite

public boolean getForQueryRewrite()

Was this node generated in a query rewrite?

Returns:

true if it was generated in a query rewrite.

setBetweenSelectivity

void setBetweenSelectivity()

Use between selectivity when calculating the selectivity.

getBetweenSelectivity

boolean getBetweenSelectivity()

Return whether or not to use the between selectivity for this node.

Returns:

Whether or not to use the between selectivity for this node.

bindExpression

public ValueNode bindExpression(FromList fromList,
                       SubqueryList subqueryList,
                       java.util.List aggregateVector)
                         throws StandardException

Bind this comparison operator. All that has to be done for binding a comparison operator is to bind the operands, check the compatibility of the types, and set the result type to SQLBoolean.

Overrides:

bindExpression in class BinaryOperatorNode

Parameters:

fromList - The query's FROM list

subqueryList - The subquery list being built as we find SubqueryNodes

aggregateVector - The aggregate vector being built as we find AggregateNodes

Returns:

The new top of the expression tree.

Throws:

StandardException - Thrown on error

bindComparisonOperator

public void bindComparisonOperator()
                            throws StandardException

Test the type compatability of the operands and set the type info for this node. This method is useful both during binding and when we generate nodes within the language module outside of the parser.

Throws:

StandardException - Thrown on error

preprocess

public ValueNode preprocess(int numTables,
                   FromList outerFromList,
                   SubqueryList outerSubqueryList,
                   PredicateList outerPredicateList)
                     throws StandardException

Preprocess an expression tree. We do a number of transformations here (including subqueries, IN lists, LIKE and BETWEEN) plus subquery flattening. NOTE: This is done before the outer ResultSetNode is preprocessed.

Overrides:

preprocess in class BinaryOperatorNode

Parameters:

numTables - Number of tables in the DML Statement

outerFromList - FromList from outer query block

outerSubqueryList - SubqueryList from outer query block

outerPredicateList - PredicateList from outer query block

Returns:

The modified expression

Throws:

StandardException - Thrown on error

eliminateNots

ValueNode eliminateNots(boolean underNotNode)
                  throws StandardException

Eliminate NotNodes in the current query block. We traverse the tree, inverting ANDs and ORs and eliminating NOTs as we go. We stop at ComparisonOperators and boolean expressions. We invert ComparisonOperators and replace boolean expressions with boolean expression = false. NOTE: Since we do not recurse under ComparisonOperators, there still could be NotNodes left in the tree.

Overrides:

eliminateNots in class ValueNode

Parameters:

underNotNode - Whether or not we are under a NotNode.

Returns:

The modified expression

Throws:

StandardException - Thrown on error

getNegation

abstract BinaryOperatorNode getNegation(ValueNode leftOperand,
                             ValueNode rightOperand)
                                 throws StandardException

Negate the comparison.

Parameters:

leftOperand - The left operand of the comparison operator

rightOperand - The right operand of the comparison operator

Returns:

BinaryOperatorNode The negated expression

Throws:

StandardException - Thrown on error

getSwappedEquivalent

abstract BinaryOperatorNode getSwappedEquivalent()
                                          throws StandardException

Return a node equivalent to this node, but with the left and right operands swapped. The node type may also be changed if the operator is not symmetric.

This method may for instance be used to normalize a predicate by moving constants to the right-hand side of the comparison. Example: 1 = A will be transformed to A = 1, and 10 < B will be transformed to B > 10.

Returns:

an equivalent expression with the operands swapped

Throws:

StandardException - if an error occurs

changeToCNF

public ValueNode changeToCNF(boolean underTopAndNode)
                      throws StandardException

Finish putting an expression into conjunctive normal form. An expression tree in conjunctive normal form meets the following criteria: o If the expression tree is not null, the top level will be a chain of AndNodes terminating in a true BooleanConstantNode. o The left child of an AndNode will never be an AndNode. o Any right-linked chain that includes an AndNode will be entirely composed of AndNodes terminated by a true BooleanConstantNode. o The left child of an OrNode will never be an OrNode. o Any right-linked chain that includes an OrNode will be entirely composed of OrNodes terminated by a false BooleanConstantNode. o ValueNodes other than AndNodes and OrNodes are considered leaf nodes for purposes of expression normalization. In other words, we won't do any normalization under those nodes. In addition, we track whether or not we are under a top level AndNode. SubqueryNodes need to know this for subquery flattening.

Overrides:

changeToCNF in class ValueNode

Parameters:

underTopAndNode - Whether or not we are under a top level AndNode.

Returns:

The modified expression

Throws:

StandardException - Thrown on error

genSQLJavaSQLTree

public ValueNode genSQLJavaSQLTree()
                            throws StandardException

Description copied from class: BinaryOperatorNode

generate a SQL->Java->SQL conversion tree above the left and right operand of this Binary Operator Node if needed. Subclasses can override the default behavior.

Overrides:

genSQLJavaSQLTree in class BinaryOperatorNode

Returns:

ValueNode The new tree.

Throws:

StandardException - Thrown on error

See Also:

BinaryOperatorNode.genSQLJavaSQLTree()