org.h2.command.dml

Class SelectUnion

java.lang.Object

org.h2.command.Prepared

org.h2.command.dml.Query

org.h2.command.dml.SelectUnion

public class SelectUnion
extends Query

Represents a union SELECT statement.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SelectUnion.UnionType

Field Summary

Fields inherited from class org.h2.command.dml.Query

distinct, limitExpr, offsetExpr, randomAccessResult, sampleSizeExpr

Fields inherited from class org.h2.command.Prepared

create, parameters, prepareAlways, session, sqlStatement

Constructor Summary

Constructors

Constructor and Description
SelectUnion(Session session, Query query)

Method Summary

Modifier and Type	Method and Description
void	addGlobalCondition(Parameter param, int columnId, int comparisonType) Add a condition to the query.
boolean	allowGlobalConditions() Check whether adding condition to the query is allowed.
void	fireBeforeSelectTriggers() Call the before triggers on all tables.
int	getColumnCount() Get the column count of this query.
double	getCost() Calculate the cost to execute this query.
LocalResult	getEmptyResult()
java.util.ArrayList<Expression>	getExpressions() The the list of select expressions.
Query	getLeft()
java.lang.String	getPlanSQL() Get the SQL statement with the execution plan.
Query	getRight()
java.util.HashSet<Table>	getTables() Get all tables that are involved in this query.
int	getType() Get the command type as defined in CommandInterface
SelectUnion.UnionType	getUnionType()
boolean	hasOrder() Whether the query has an order.
void	init() Initialize the query.
boolean	isEverything(ExpressionVisitor visitor) Check if this expression and all sub-expressions can fulfill a criteria.
boolean	isReadOnly() Check if this command is read only.
boolean	isUnion() Check if this is a UNION query.
void	mapColumns(ColumnResolver resolver, int level) Map the columns to the given column resolver.
void	prepare() Prepare this statement.
void	prepareJoinBatch() Prepare join batching.
ResultInterface	queryMeta() Get an empty result set containing the meta data.
protected ResultInterface	queryWithoutCache(int maxRows, ResultTarget target) Execute the query without checking the cache.
void	setEvaluatable(TableFilter tableFilter, boolean b) Change the evaluatable flag.
void	setForUpdate(boolean forUpdate) Set the 'for update' flag.
void	setOrder(java.util.ArrayList<SelectOrderBy> order) Set the order by list.
void	setRight(Query select)
void	setSQL(java.lang.String sql) Set the SQL statement.
void	setUnionType(SelectUnion.UnionType type)
void	updateAggregate(Session s) Update all aggregate function values.

Methods inherited from class org.h2.command.dml.Query

disableCache, getCostAsExpression, getLimit, getMaxDataModificationId, getOffset, getParameterValues, isDistinct, isNeverLazy, isQuery, isTransactional, prepareOrder, query, query, setDistinct, setLimit, setNeverLazy, setOffset, setRandomAccessResult, setSampleSize

Methods inherited from class org.h2.command.Prepared

checkCanceled, checkParameters, getCteCleanups, getCurrentObjectId, getCurrentRowNumber, getObjectId, getParameters, getSession, getSQL, getSQL, getSQL, isCacheable, needRecompile, setCommand, setCteCleanups, setCurrentRowNumber, setObjectId, setParameterList, setPrepareAlways, setRow, setSession, toString, update

Methods inherited from class java.lang.Object

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

Constructor Detail

SelectUnion

public SelectUnion(Session session,
                   Query query)

Method Detail

isUnion

public boolean isUnion()

Description copied from class: Query

Check if this is a UNION query.

Specified by:

isUnion in class Query

Returns:

true if this is a UNION query

prepareJoinBatch

public void prepareJoinBatch()

Description copied from class: Query

Prepare join batching.

Specified by:

prepareJoinBatch in class Query

setUnionType

public void setUnionType(SelectUnion.UnionType type)

getUnionType

public SelectUnion.UnionType getUnionType()

setRight

public void setRight(Query select)

getLeft

public Query getLeft()

getRight

public Query getRight()

setSQL

public void setSQL(java.lang.String sql)

Description copied from class: Prepared

Set the SQL statement.

Overrides:

setSQL in class Prepared

Parameters:

sql - the SQL statement

setOrder

public void setOrder(java.util.ArrayList<SelectOrderBy> order)

Description copied from class: Query

Set the order by list.

Specified by:

setOrder in class Query

Parameters:

order - the order by list

hasOrder

public boolean hasOrder()

Description copied from class: Query

Whether the query has an order.

Specified by:

hasOrder in class Query

Returns:

true if it has

queryMeta

public ResultInterface queryMeta()

Description copied from class: Prepared

Get an empty result set containing the meta data.

Specified by:

queryMeta in class Prepared

Returns:

the result set

getEmptyResult

public LocalResult getEmptyResult()

queryWithoutCache

protected ResultInterface queryWithoutCache(int maxRows,
                                            ResultTarget target)

Description copied from class: Query

Execute the query without checking the cache. If a target is specified, the results are written to it, and the method returns null. If no target is specified, a new LocalResult is created and returned.

Specified by:

queryWithoutCache in class Query

Parameters:

maxRows - the limit as specified in the JDBC method call

target - the target to write results to

Returns:

the result

init

public void init()

Description copied from class: Query

Initialize the query.

Specified by:

init in class Query

prepare

public void prepare()

Description copied from class: Prepared

Prepare this statement.

Overrides:

prepare in class Prepared

getCost

public double getCost()

Description copied from class: Query

Calculate the cost to execute this query.

Specified by:

getCost in class Query

Returns:

the cost

getTables

public java.util.HashSet<Table> getTables()

Description copied from class: Query

Get all tables that are involved in this query.

Specified by:

getTables in class Query

Returns:

the set of tables

getExpressions

public java.util.ArrayList<Expression> getExpressions()

Description copied from class: Query

The the list of select expressions. This may include invisible expressions such as order by expressions.

Specified by:

getExpressions in class Query

Returns:

the list of expressions

setForUpdate

public void setForUpdate(boolean forUpdate)

Description copied from class: Query

Set the 'for update' flag.

Specified by:

setForUpdate in class Query

Parameters:

forUpdate - the new setting

getColumnCount

public int getColumnCount()

Description copied from class: Query

Get the column count of this query.

Specified by:

getColumnCount in class Query

Returns:

the column count

mapColumns

public void mapColumns(ColumnResolver resolver,
                       int level)

Description copied from class: Query

Map the columns to the given column resolver.

Specified by:

mapColumns in class Query

Parameters:

resolver - the resolver

level - the subquery level (0 is the top level query, 1 is the first subquery level)

setEvaluatable

public void setEvaluatable(TableFilter tableFilter,
                           boolean b)

Description copied from class: Query

Change the evaluatable flag. This is used when building the execution plan.

Specified by:

setEvaluatable in class Query

Parameters:

tableFilter - the table filter

b - the new value

addGlobalCondition

public void addGlobalCondition(Parameter param,
                               int columnId,
                               int comparisonType)

Description copied from class: Query

Add a condition to the query. This is used for views.

Specified by:

addGlobalCondition in class Query

Parameters:

param - the parameter

columnId - the column index (0 meaning the first column)

comparisonType - the comparison type

getPlanSQL

public java.lang.String getPlanSQL()

Description copied from class: Prepared

Get the SQL statement with the execution plan.

Overrides:

getPlanSQL in class Prepared

Returns:

the execution plan

isEverything

public boolean isEverything(ExpressionVisitor visitor)

Description copied from class: Query

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 Query

Parameters:

visitor - the visitor

Returns:

if the criteria can be fulfilled

isReadOnly

public boolean isReadOnly()

Description copied from class: Prepared

Check if this command is read only.

Overrides:

isReadOnly in class Prepared

Returns:

true if it is

updateAggregate

public void updateAggregate(Session s)

Description copied from class: Query

Update all aggregate function values.

Specified by:

updateAggregate in class Query

Parameters:

s - the session

fireBeforeSelectTriggers

public void fireBeforeSelectTriggers()

Description copied from class: Query

Call the before triggers on all tables.

Specified by:

fireBeforeSelectTriggers in class Query

getType

public int getType()

Description copied from class: Prepared

Get the command type as defined in CommandInterface

Specified by:

getType in class Prepared

Returns:

the statement type

allowGlobalConditions

public boolean allowGlobalConditions()

Description copied from class: Query

Check whether adding condition to the query is allowed. This is not allowed for views that have an order by and a limit, as it would affect the returned results.

Specified by:

allowGlobalConditions in class Query

Returns:

true if adding global conditions is allowed