org.h2.expression.condition

Class CompareLike

java.lang.Object

org.h2.expression.Expression

org.h2.expression.condition.CompareLike

public class CompareLike
extends Expression

Pattern matching comparison expression: WHERE NAME LIKE ?

Field Summary

Fields inherited from class org.h2.expression.Expression

MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL

Constructor Summary

Constructors

Constructor and Description
CompareLike(CompareMode compareMode, java.lang.String defaultEscape, Expression left, Expression right, Expression escape, boolean regexp)
CompareLike(Database db, Expression left, Expression right, Expression escape, boolean regexp)

Method Summary

Methods

Modifier and Type	Method and Description
void	createIndexConditions(Session session, TableFilter filter) Create index conditions if possible and attach them to the table filter.
int	getCost() Estimate the cost to process the expression.
java.lang.StringBuilder	getSQL(java.lang.StringBuilder builder) Appends the SQL statement of this expression to the specified builder.
Expression	getSubexpression(int index) Returns subexpression with specified index.
int	getSubexpressionCount() Returns count of subexpressions.
TypeInfo	getType() Returns the data type.
Value	getValue(Session session) Return the resulting value for the current row.
boolean	isEverything(ExpressionVisitor visitor) Check if this expression and all sub-expressions can fulfill a criteria.
void	mapColumns(ColumnResolver resolver, int level, int state) Map the columns of the resolver to expression columns.
Expression	optimize(Session session) Try to optimize the expression.
void	setEvaluatable(TableFilter tableFilter, boolean b) Tell the expression columns whether the table filter can return values now.
boolean	test(java.lang.String testPattern, java.lang.String value, char escapeChar) Test if the value matches the pattern.
void	updateAggregate(Session session, int stage) Update an aggregate value.

Methods inherited from class org.h2.expression.Expression

addFilterConditions, getAlias, getBooleanValue, getColumnName, getExpressionColumns, getExpressionColumns, getExpressionColumns, getNonAliasExpression, getNotIfPossible, getNullable, getSchemaName, getSQL, getTableAlias, getTableName, getUnenclosedSQL, isAutoIncrement, isConstant, isGeneratedKey, isValueSet, toString, writeExpressions, writeExpressions

Methods inherited from class java.lang.Object

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

Constructor Detail

CompareLike

public CompareLike(Database db,
           Expression left,
           Expression right,
           Expression escape,
           boolean regexp)

CompareLike

public CompareLike(CompareMode compareMode,
           java.lang.String defaultEscape,
           Expression left,
           Expression right,
           Expression escape,
           boolean regexp)

Method Detail

getSQL

public java.lang.StringBuilder getSQL(java.lang.StringBuilder builder)

Description copied from class: Expression

Appends the SQL statement of this expression to the specified builder. This may not always be the original SQL statement, specially after optimization.

Specified by:

getSQL in class Expression

Parameters:

builder - string builder

Returns:

the specified string builder

optimize

public Expression optimize(Session session)

Description copied from class: Expression

Try to optimize the expression.

Specified by:

optimize in class Expression

Parameters:

session - the session

Returns:

the optimized expression

createIndexConditions

public void createIndexConditions(Session session,
                         TableFilter filter)

Description copied from class: Expression

Create index conditions if possible and attach them to the table filter.

Overrides:

createIndexConditions in class Expression

Parameters:

session - the session

filter - the table filter

getValue

public Value getValue(Session session)

Description copied from class: Expression

Return the resulting value for the current row.

Specified by:

getValue in class Expression

Parameters:

session - the session

Returns:

the result

test

public boolean test(java.lang.String testPattern,
           java.lang.String value,
           char escapeChar)

Test if the value matches the pattern.

Parameters:

testPattern - the pattern

value - the value

escapeChar - the escape character

Returns:

true if the value matches

mapColumns

public void mapColumns(ColumnResolver resolver,
              int level,
              int state)

Description copied from class: Expression

Map the columns of the resolver to expression columns.

Specified by:

mapColumns in class Expression

Parameters:

resolver - the column resolver

level - the subquery nesting level

state - current state for nesting checks, initial value is Expression.MAP_INITIAL

setEvaluatable

public void setEvaluatable(TableFilter tableFilter,
                  boolean b)

Description copied from class: Expression

Tell the expression columns whether the table filter can return values now. This is used when optimizing the query.

Specified by:

setEvaluatable in class Expression

Parameters:

tableFilter - the table filter

b - true if the table filter can return value

updateAggregate

public void updateAggregate(Session session,
                   int stage)

Description copied from class: Expression

Update an aggregate value. This method is called at statement execution time. It is usually called once for each row, but if the expression is used multiple times (for example in the column list, and as part of the HAVING expression) it is called multiple times - the row counter needs to be used to make sure the internal state is only updated once.

Specified by:

updateAggregate in class Expression

Parameters:

session - the session

stage - select stage

isEverything

public boolean isEverything(ExpressionVisitor visitor)

Description copied from class: Expression

Check if this expression and all sub-expressions can fulfill a criteria. If any part returns false, the result is false.

Specified by:

isEverything in class Expression

Parameters:

visitor - the visitor

Returns:

if the criteria can be fulfilled

getCost

public int getCost()

Description copied from class: Expression

Estimate the cost to process the expression. Used when optimizing the query, to calculate the query plan with the lowest estimated cost.

Specified by:

getCost in class Expression

Returns:

the estimated cost

getSubexpressionCount

public int getSubexpressionCount()

Description copied from class: Expression

Returns count of subexpressions.

Overrides:

getSubexpressionCount in class Expression

Returns:

count of subexpressions

getSubexpression

public Expression getSubexpression(int index)

Description copied from class: Expression

Returns subexpression with specified index.

Overrides:

getSubexpression in class Expression

Parameters:

index - 0-based index

Returns:

subexpression with specified index

getType

public TypeInfo getType()

Description copied from class: Expression

Returns the data type. The data type may not be known before the optimization phase.

Specified by:

getType in class Expression

Returns:

the data type