org.h2.expression

Class ConditionAndOr

java.lang.Object

org.h2.expression.Expression

org.h2.expression.ConditionAndOr

public class ConditionAndOr
extends Expression

An 'and' or 'or' condition as in WHERE ID=1 AND NAME=?

Field Summary

Fields

Modifier and Type	Field and Description
static int	AND The AND condition type as in ID=1 AND NAME='Hello'.
static int	OR The OR condition type as in ID=1 OR NAME='Hello'.

Constructor Summary

Constructors

Constructor and Description
ConditionAndOr(int andOrType, Expression left, Expression right)

Method Summary

Modifier and Type	Method and Description
void	addFilterConditions(TableFilter filter, boolean outerJoin) Add conditions to a table filter if they can be evaluated.
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.
int	getDisplaySize() Get the display size of this expression.
Expression	getExpression(boolean getLeft) Get the left or the right sub-expression of this condition.
Expression	getNotIfPossible(Session session) If it is possible, return the negated expression.
long	getPrecision() Get the precision of this expression.
int	getScale() Get the scale of this expression.
java.lang.String	getSQL() Get the SQL statement of this expression.
int	getType() Return 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) 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.
void	updateAggregate(Session session) Update an aggregate value.

Methods inherited from class org.h2.expression.Expression

getAlias, getBooleanValue, getColumnName, getExpressionColumns, getExpressionColumns, getNonAliasExpression, getNullable, getSchemaName, getTableAlias, getTableName, isAutoIncrement, isConstant, isValueSet, isWildcard, toString

Methods inherited from class java.lang.Object

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

Field Detail

AND

public static final int AND

The AND condition type as in ID=1 AND NAME='Hello'.

See Also:

Constant Field Values

OR

public static final int OR

The OR condition type as in ID=1 OR NAME='Hello'.

See Also:

Constant Field Values

Constructor Detail

ConditionAndOr

public ConditionAndOr(int andOrType,
                      Expression left,
                      Expression right)

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

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

getNotIfPossible

public Expression getNotIfPossible(Session session)

Description copied from class: Expression

If it is possible, return the negated expression. This is used to optimize NOT expressions: NOT ID>10 can be converted to ID<=10. Returns null if negating is not possible.

Overrides:

getNotIfPossible in class Expression

Parameters:

session - the session

Returns:

the negated expression, or null

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

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

addFilterConditions

public void addFilterConditions(TableFilter filter,
                                boolean outerJoin)

Description copied from class: Expression

Add conditions to a table filter if they can be evaluated.

Overrides:

addFilterConditions in class Expression

Parameters:

filter - the table filter

outerJoin - if the expression is part of an outer join

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

getExpression

public Expression getExpression(boolean getLeft)

Get the left or the right sub-expression of this condition.

Parameters:

getLeft - true to get the left sub-expression, false to get the right sub-expression.

Returns:

the sub-expression

getType

public int getType()

Description copied from class: Expression

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

Specified by:

getType in class Expression

Returns:

the type

getScale

public int getScale()

Description copied from class: Expression

Get the scale of this expression.

Specified by:

getScale in class Expression

Returns:

the scale

getPrecision

public long getPrecision()

Description copied from class: Expression

Get the precision of this expression.

Specified by:

getPrecision in class Expression

Returns:

the precision

getDisplaySize

public int getDisplaySize()

Description copied from class: Expression

Get the display size of this expression.

Specified by:

getDisplaySize in class Expression

Returns:

the display size