org.apache.derby.impl.sql.compile

Class LikeEscapeOperatorNode

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.TernaryOperatorNode

org.apache.derby.impl.sql.compile.LikeEscapeOperatorNode

All Implemented Interfaces:

Node, Visitable

public final class LikeEscapeOperatorNode
extends TernaryOperatorNode

This node represents a like comparison operator (no escape) If the like pattern is a constant or a parameter then if possible the like is modified to include a >= and < operator. In some cases the like can be eliminated. By adding =, >= or < operators it may allow indexes to be used to greatly narrow the search range of the query, and allow optimizer to estimate number of rows to affected. constant or parameter LIKE pattern with prefix followed by optional wild card e.g. Derby% CHAR(n), VARCHAR(n) where n < 255 >= prefix padded with '' to length n -- e.g. Derby <= prefix appended with '?' -- e.g. Derby? [ can eliminate LIKE if constant. ] CHAR(n), VARCHAR(n), LONG VARCHAR where n >= 255 >= prefix backed up one characer <= prefix appended with '?' no elimination of like parameter like pattern starts with wild card e.g. %Derby CHAR(n), VARCHAR(n) where n <= 256 >= '' padded with '' to length n <= '?' no elimination of like CHAR(n), VARCHAR(n), LONG VARCHAR where n > 256 >= NULL <= '?' Note that the Unicode value '?' is defined as not a character value and can be used by a program for any purpose. We use it to set an upper bound on a character range with a less than predicate. We only need a single '?' appended because the string 'Derby??' is not a valid String because '?' is not a valid character.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) boolean	addedEquals Fields of the class
(package private) java.lang.String	escape

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

leftInterfaceType, leftOperand, LIKE, LOCATE, methodName, operator, operatorType, receiver, receiverInterfaceType, resultInterfaceType, rightInterfaceType, rightOperand, SUBSTRING, TernaryArgType, TernaryMethodNames, TernaryOperators, TernaryResultType, TIMESTAMPADD, TIMESTAMPDIFF, TRIM, trimType

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
LikeEscapeOperatorNode()

Method Summary

Modifier and Type	Method and Description
void	bindComparisonOperator() Bind this operator
ValueNode	bindExpression(FromList fromList, SubqueryList subqueryList, java.util.List aggregateVector) implement binding for like expressions.
private void	finishBindExpr()
void	generateExpression(ExpressionClassBuilder acb, MethodBuilder mb) Do code generation for this binary operator.
void	init(java.lang.Object receiver, java.lang.Object leftOperand, java.lang.Object rightOperand) Initializer for a LikeEscapeOperatorNode receiver like pattern [ escape escapeValue ]
ValueNode	preprocess(int numTables, FromList outerFromList, SubqueryList outerSubqueryList, PredicateList outerPredicateList) Preprocess an expression tree.
private ValueNode	setupOptimizeStringFromParameter(ValueNode parameterNode, ValueNode escapeNode, java.lang.String methodName, int maxWidth)

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

acceptChildren, bindToBuiltIn, castArgToString, categorize, constantExpression, getLeftOperand, getReceiver, getRightOperand, init, isConstantExpression, isEquivalent, locateBind, printSubNodes, remapColumnReferencesToExpressions, setLeftOperand, setRightOperand, substrBind, 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, changeToCNF, checkIsBoolean, checkTopPredicatesForEqualsConditions, copyFields, eliminateNots, evaluateConstantExpressions, genEqualsFalseTree, generate, generateFilter, genIsNullTree, genSQLJavaSQLTree, getClone, getColumnName, getConstantValueAsObject, getDataValueFactory, getOrderableVariantType, 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, 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

addedEquals

boolean addedEquals

Fields of the class

escape

java.lang.String escape

Constructor Detail

LikeEscapeOperatorNode

public LikeEscapeOperatorNode()

Method Detail

init

public void init(java.lang.Object receiver,
                 java.lang.Object leftOperand,
                 java.lang.Object rightOperand)

Initializer for a LikeEscapeOperatorNode receiver like pattern [ escape escapeValue ]

Specified by:

init in interface Node

Overrides:

init in class QueryTreeNode

Parameters:

receiver - The left operand of the like: column, CharConstant or Parameter

leftOperand - The right operand of the like: the pattern

rightOperand - The optional escape clause, null if not present

bindExpression

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

implement binding for like expressions.

overrides BindOperatorNode.bindExpression because like has special requirements for parameter binding.

Overrides:

bindExpression in class TernaryOperatorNode

Parameters:

fromList - The FROM list for the query this expression is in, for binding columns.

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 failure

finishBindExpr

private void finishBindExpr()
                     throws StandardException

Throws:

StandardException

bindComparisonOperator

public void bindComparisonOperator()
                            throws StandardException

Bind this operator

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 TernaryOperatorNode

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

generateExpression

public void generateExpression(ExpressionClassBuilder acb,
                               MethodBuilder mb)
                        throws StandardException

Do code generation for this binary operator. This code was copied from BinaryOperatorNode and stripped down

Overrides:

generateExpression in class TernaryOperatorNode

Parameters:

acb - The ExpressionClassBuilder for the class we're generating

mb - The method the code to place the code

Throws:

StandardException - Thrown on error

setupOptimizeStringFromParameter

private ValueNode setupOptimizeStringFromParameter(ValueNode parameterNode,
                                                   ValueNode escapeNode,
                                                   java.lang.String methodName,
                                                   int maxWidth)
                                            throws StandardException

Throws:

StandardException