com.akiban.sql.parser
Class LikeEscapeOperatorNode

java.lang.Object
  com.akiban.sql.parser.QueryTreeNode
      com.akiban.sql.parser.ValueNode
          com.akiban.sql.parser.TernaryOperatorNode
              com.akiban.sql.parser.LikeEscapeOperatorNode

All Implemented Interfaces:

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.

Nested Class Summary

Nested classes/interfaces inherited from class com.akiban.sql.parser.TernaryOperatorNode

TernaryOperatorNode.OperatorType

Field Summary

Fields inherited from class com.akiban.sql.parser.TernaryOperatorNode

DAY_INTERVAL, FRAC_SECOND_INTERVAL, HOUR_INTERVAL, leftInterfaceType, leftOperand, methodName, MINUTE_INTERVAL, MONTH_INTERVAL, operator, operatorType, QUARTER_INTERVAL, receiver, receiverInterfaceType, resultInterfaceType, rightInterfaceType, rightOperand, SECOND_INTERVAL, WEEK_INTERVAL, YEAR_INTERVAL

Fields inherited from class com.akiban.sql.parser.QueryTreeNode

AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX

Constructor Summary

LikeEscapeOperatorNode()

Method Summary

void	init(Object receiver, Object leftOperand, Object rightOperand) Initializer for a LikeEscapeOperatorNode receiver like pattern [ escape escapeValue ]

Methods inherited from class com.akiban.sql.parser.TernaryOperatorNode

copyFrom, getLeftOperand, getMethodName, getOperator, getReceiver, getRightOperand, init, isEquivalent, printSubNodes, setLeftOperand, setReceiver, setRightOperand, toString

Methods inherited from class com.akiban.sql.parser.ValueNode

getColumnName, getSchemaName, getSourceResultColumn, getTableName, getType, getTypeId, isBinaryEqualsOperatorNode, isBooleanFalse, isBooleanTrue, isConstantExpression, isInListProbeNode, isParameterNode, isRelationalOperator, isSameNodeType, setNullability, setType

Methods inherited from class com.akiban.sql.parser.QueryTreeNode

accept, convertDefaultNode, debugFlush, debugPrint, formatNodeString, getBeginOffset, getDebugOutput, getEndOffset, getNodeFactory, getNodeType, getNullNode, getParserContext, getStatementType, getUserData, init, init, init, init, init, init, init, init, init, init, init, init, isInstanceOf, makeTableName, makeTableName, nodeHeader, printLabel, setBeginOffset, setDebugOutput, setEndOffset, setNodeType, setParserContext, setUserData, stackPrint, treePrint, treePrint, treePrint

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

LikeEscapeOperatorNode

public LikeEscapeOperatorNode()

Method Detail

init

public void init(Object receiver,
                 Object leftOperand,
                 Object rightOperand)

Initializer for a LikeEscapeOperatorNode receiver like pattern [ escape escapeValue ]

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