org.h2.expression
Class CompareLike

java.lang.Object
  org.h2.expression.Expression
      org.h2.expression.Condition
          org.h2.expression.CompareLike

public class CompareLike
extends Condition

Pattern matching comparison expression: WHERE NAME LIKE ?

Constructor Summary

CompareLike(CompareMode compareMode, Expression left, Expression right, Expression escape, boolean regexp)

Method Summary

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.String	getSQL() Get the SQL statement of this expression.
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) 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) Update an aggregate value.

Methods inherited from class org.h2.expression.Condition

getDisplaySize, getPrecision, getScale, getType

Methods inherited from class org.h2.expression.Expression

addFilterConditions, getAlias, getBooleanValue, getColumnName, getNonAliasExpression, getNotIfPossible, getNullable, getSchemaName, getTableAlias, getTableName, isAutoIncrement, isConstant, isEverything, isValueSet, isWildcard, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

CompareLike

public CompareLike(CompareMode compareMode,
                   Expression left,
                   Expression right,
                   Expression escape,
                   boolean regexp)

Method Detail

getSQL

public java.lang.String getSQL()

Description copied from class: Expression

Get the SQL statement of this expression. This may not always be the original SQL statement, specially after optimization.

Specified by:

getSQL in class Expression

Returns:

the SQL statement

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)

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

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)

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

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