org.h2.table
Class TableFilter

java.lang.Object
  org.h2.table.TableFilter

All Implemented Interfaces:

ColumnResolver

public class TableFilter
extends java.lang.Object
implements ColumnResolver

A table filter represents a table that is used in a query. There is one such object whenever a table (or view) is used in a query. For example the following query has 2 table filters: SELECT * FROM TEST T1, TEST T2.

Constructor Summary

TableFilter(Session session, Table table, java.lang.String alias, boolean rightsChecked, Select select)
Create a new table filter object.

Method Summary

void	addFilterCondition(Expression condition, boolean join) Add a filter condition.
void	addIndexCondition(IndexCondition condition) Add an index condition.
void	addJoin(TableFilter filter, boolean outer, Expression on) Add a joined table.
void	addNaturalJoinColumn(Column c) Add a column to the natural join key column list.
Row	get() Get the current row.
PlanItem	getBestPlanItem(Session session, int level) Get the best plan item (index, cost) to use use for the current join order.
Column[]	getColumns() Get the column list.
Expression	getFilterCondition()
Index	getIndex()
TableFilter	getJoin()
Expression	getJoinCondition()
java.lang.String	getPlanSQL(boolean join) Get the query execution plan text to use for this table filter.
java.lang.String	getSchemaName() Get the schema name.
Select	getSelect() Get the select statement.
Column[]	getSystemColumns() Get the system columns that this table understands.
Table	getTable()
java.lang.String	getTableAlias() Get the table alias name.
TableFilter	getTableFilter() Get the table filter.
Value	getValue(Column column) Get the value for the given column.
int	hashCode()
boolean	hasInComparisons() Are there any index conditions that involve IN(...).
boolean	isJoinOuter() Check if this is an outer joined table.
boolean	isNaturalJoinColumn(Column c) Check if the given column is a natural join column.
boolean	isUsed()
void	lock(Session session, boolean exclusive, boolean force) Lock the table.
void	mapAndAddFilter(Expression on) Map the columns and add the join condition.
boolean	next() Check if there are more rows to read.
Expression	optimize(ExpressionColumn expressionColumn, Column column) Get the expression that represents this column.
void	prepare() Prepare reading rows.
void	removeFilterCondition() Remove the filter condition.
void	removeJoin() Remove the joined table
void	removeJoinCondition() Remove the join condition.
void	reset() Reset to the current position.
void	set(Row current) Set the current row.
void	setAlias(java.lang.String alias)
void	setEvaluatable(TableFilter filter, boolean b) Update the filter and join conditions of this and all joined tables with the information that the given table filter can now return rows or not.
void	setFullCondition(Expression condition)
void	setIndex(Index index)
void	setPlanItem(PlanItem item) Set what plan item (index, cost) to use use.
void	setUsed(boolean used)
void	startQuery(Session session) Start the query.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

TableFilter

public TableFilter(Session session,
                   Table table,
                   java.lang.String alias,
                   boolean rightsChecked,
                   Select select)
            throws java.sql.SQLException

Create a new table filter object.

Parameters:

session - the session

table - the table from where to read data

alias - the alias name

rightsChecked - true if rights are already checked

select - the select statement

Throws:

java.sql.SQLException

Method Detail

getSelect

public Select getSelect()

Description copied from interface: ColumnResolver

Get the select statement.

Specified by:

getSelect in interface ColumnResolver

Returns:

the select statement

getTable

public Table getTable()

lock

public void lock(Session session,
                 boolean exclusive,
                 boolean force)
          throws java.sql.SQLException

Lock the table. This will also lock joined tables.

Parameters:

session - the session

exclusive - true if an exclusive lock is required

force - lock even in the MVCC mode

Throws:

java.sql.SQLException

getBestPlanItem

public PlanItem getBestPlanItem(Session session,
                                int level)
                         throws java.sql.SQLException

Get the best plan item (index, cost) to use use for the current join order.

Parameters:

session - the session

level - 1 for the first table in a join, 2 for the second, and so on

Returns:

the best plan item

Throws:

java.sql.SQLException

setPlanItem

public void setPlanItem(PlanItem item)

Set what plan item (index, cost) to use use.

Parameters:

item - the plan item

prepare

public void prepare()
             throws java.sql.SQLException

Prepare reading rows. This method will remove all index conditions that can not be used, and optimize the conditions.

Throws:

java.sql.SQLException

startQuery

public void startQuery(Session session)

Start the query. This will reset the scan counts.

Parameters:

session - the session

reset

public void reset()

Reset to the current position.

next

public boolean next()
             throws java.sql.SQLException

Check if there are more rows to read.

Returns:

true if there are

Throws:

java.sql.SQLException

get

public Row get()
        throws java.sql.SQLException

Get the current row.

Returns:

the current row, or null

Throws:

java.sql.SQLException

set

public void set(Row current)

Set the current row.

Parameters:

current - the current row

getTableAlias

public java.lang.String getTableAlias()

Get the table alias name. If no alias is specified, the table name is returned.

Specified by:

getTableAlias in interface ColumnResolver

Returns:

the alias name

addIndexCondition

public void addIndexCondition(IndexCondition condition)

Add an index condition.

Parameters:

condition - the index condition

addFilterCondition

public void addFilterCondition(Expression condition,
                               boolean join)

Add a filter condition.

Parameters:

condition - the condition

join - if this is in fact a join condition

addJoin

public void addJoin(TableFilter filter,
                    boolean outer,
                    Expression on)
             throws java.sql.SQLException

Add a joined table.

Parameters:

filter - the joined table filter

outer - if this is an outer join

on - the join condition

Throws:

java.sql.SQLException

mapAndAddFilter

public void mapAndAddFilter(Expression on)
                     throws java.sql.SQLException

Map the columns and add the join condition.

Parameters:

on - the condition

Throws:

java.sql.SQLException

getJoin

public TableFilter getJoin()

isJoinOuter

public boolean isJoinOuter()

Check if this is an outer joined table.

Returns:

true if it is

getPlanSQL

public java.lang.String getPlanSQL(boolean join)

Get the query execution plan text to use for this table filter.

Parameters:

join - if this is a joined table

Returns:

the SQL statement snippet

getIndex

public Index getIndex()

setIndex

public void setIndex(Index index)

setUsed

public void setUsed(boolean used)

isUsed

public boolean isUsed()

removeJoin

public void removeJoin()

Remove the joined table

getJoinCondition

public Expression getJoinCondition()

removeJoinCondition

public void removeJoinCondition()

Remove the join condition.

getFilterCondition

public Expression getFilterCondition()

removeFilterCondition

public void removeFilterCondition()

Remove the filter condition.

setFullCondition

public void setFullCondition(Expression condition)

setEvaluatable

public void setEvaluatable(TableFilter filter,
                           boolean b)

Update the filter and join conditions of this and all joined tables with the information that the given table filter can now return rows or not.

Parameters:

filter - the table filter

b - the new flag

getSchemaName

public java.lang.String getSchemaName()

Description copied from interface: ColumnResolver

Get the schema name.

Specified by:

getSchemaName in interface ColumnResolver

Returns:

the schema name

getColumns

public Column[] getColumns()

Description copied from interface: ColumnResolver

Get the column list.

Specified by:

getColumns in interface ColumnResolver

Returns:

the column list

getSystemColumns

public Column[] getSystemColumns()

Get the system columns that this table understands. This is used for compatibility with other databases. The columns are only returned if the current mode supports system columns.

Specified by:

getSystemColumns in interface ColumnResolver

Returns:

the system columns

getValue

public Value getValue(Column column)
               throws java.sql.SQLException

Description copied from interface: ColumnResolver

Get the value for the given column.

Specified by:

getValue in interface ColumnResolver

Parameters:

column - the column

Returns:

the value

Throws:

java.sql.SQLException

getTableFilter

public TableFilter getTableFilter()

Description copied from interface: ColumnResolver

Get the table filter.

Specified by:

getTableFilter in interface ColumnResolver

Returns:

the table filter

setAlias

public void setAlias(java.lang.String alias)

optimize

public Expression optimize(ExpressionColumn expressionColumn,
                           Column column)

Description copied from interface: ColumnResolver

Get the expression that represents this column.

Specified by:

optimize in interface ColumnResolver

Parameters:

expressionColumn - the expression column

column - the column

Returns:

the optimized expression

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

addNaturalJoinColumn

public void addNaturalJoinColumn(Column c)

Add a column to the natural join key column list.

Parameters:

c - the column to add

isNaturalJoinColumn

public boolean isNaturalJoinColumn(Column c)

Check if the given column is a natural join column.

Parameters:

c - the column to check

Returns:

true if this is a joined natural join column

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

hasInComparisons

public boolean hasInComparisons()

Are there any index conditions that involve IN(...).

Returns:

whether there are IN(...) comparisons