org.h2.index

Class VirtualConstructedTableIndex

java.lang.Object

org.h2.engine.DbObjectBase

org.h2.schema.SchemaObjectBase

org.h2.index.BaseIndex

org.h2.index.VirtualTableIndex

org.h2.index.VirtualConstructedTableIndex

All Implemented Interfaces:

DbObject, Index, SchemaObject

public class VirtualConstructedTableIndex
extends VirtualTableIndex

An index for a virtual table that returns a result set. Search in this index performs scan over all rows and should be avoided.

Field Summary

Fields inherited from class org.h2.index.BaseIndex

columnIds, columns, indexColumns, indexType

Fields inherited from class org.h2.engine.DbObjectBase

comment, database, trace

Fields inherited from interface org.h2.engine.DbObject

AGGREGATE, COMMENT, CONSTANT, CONSTRAINT, DOMAIN, FUNCTION_ALIAS, INDEX, RIGHT, ROLE, SCHEMA, SEQUENCE, SETTING, SYNONYM, TABLE_OR_VIEW, TRIGGER, USER

Constructor Summary

Constructors

Constructor and Description
VirtualConstructedTableIndex(VirtualConstructedTable table, IndexColumn[] columns)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	canGetFirstOrLast() Check if the index can directly look up the lowest or highest value of a column.
boolean	canScan() Can this index iterate over all rows?
Cursor	find(Session session, SearchRow first, SearchRow last) Find a row or a list of rows and create a cursor to iterate over the result.
double	getCost(Session session, int[] masks, TableFilter[] filters, int filter, SortOrder sortOrder, AllColumnsForPlan allColumnsSet) Estimate the cost to search for rows given the search mask.
java.lang.String	getPlanSQL() Get the message to show in a EXPLAIN statement.
boolean	isFindUsingFullTableScan() Returns true if find() implementation performs scan over all index, false if find() performs the fast lookup.

Methods inherited from class org.h2.index.VirtualTableIndex

add, checkRename, close, findFirstOrLast, getDiskSpaceUsed, getRowCount, getRowCountApproximation, needRebuild, remove, remove, truncate

Methods inherited from class org.h2.index.BaseIndex

canFindNext, checkIndexColumnTypes, compareKeys, compareRows, createLookupBatch, find, findNext, getColumnIndex, getColumns, getCostRangeIndex, getCreateSQL, getCreateSQLForCopy, getDropSQL, getDuplicateKeyException, getDuplicatePrimaryKeyMessage, getIndexColumns, getIndexType, getRow, getTable, getType, isFirstColumn, isHidden, isRowIdIndex, mayHaveNullDuplicates, removeChildrenAndResources, setSortedInsertMode, update

Methods inherited from class org.h2.schema.SchemaObjectBase

getSchema, getSQL, getSQL

Methods inherited from class org.h2.engine.DbObjectBase

getChildren, getComment, getDatabase, getId, getModificationId, getName, invalidate, isTemporary, isValid, rename, setComment, setModified, setObjectName, setTemporary, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.h2.schema.SchemaObject

getSchema

Methods inherited from interface org.h2.engine.DbObject

getChildren, getComment, getDatabase, getId, getName, getSQL, getSQL, isTemporary, rename, setComment, setTemporary

Constructor Detail

VirtualConstructedTableIndex

public VirtualConstructedTableIndex(VirtualConstructedTable table,
                            IndexColumn[] columns)

Method Detail

isFindUsingFullTableScan

public boolean isFindUsingFullTableScan()

Description copied from interface: Index

Returns true if find() implementation performs scan over all index, false if find() performs the fast lookup.

Specified by:

isFindUsingFullTableScan in interface Index

Overrides:

isFindUsingFullTableScan in class BaseIndex

Returns:

true if find() implementation performs scan over all index, false if find() performs the fast lookup

find

public Cursor find(Session session,
          SearchRow first,
          SearchRow last)

Description copied from interface: Index

Find a row or a list of rows and create a cursor to iterate over the result.

Parameters:

session - the session

first - the first row, or null for no limit

last - the last row, or null for no limit

Returns:

the cursor to iterate over the results

getCost

public double getCost(Session session,
             int[] masks,
             TableFilter[] filters,
             int filter,
             SortOrder sortOrder,
             AllColumnsForPlan allColumnsSet)

Description copied from interface: Index

Estimate the cost to search for rows given the search mask. There is one element per column in the search mask. For possible search masks, see IndexCondition.

Parameters:

session - the session

masks - per-column comparison bit masks, null means 'always false', see constants in IndexCondition

filters - all joined table filters

filter - the current table filter index

sortOrder - the sort order

allColumnsSet - the set of all columns

Returns:

the estimated cost

canGetFirstOrLast

public boolean canGetFirstOrLast()

Description copied from interface: Index

Check if the index can directly look up the lowest or highest value of a column.

Returns:

true if it can

getPlanSQL

public java.lang.String getPlanSQL()

Description copied from interface: Index

Get the message to show in a EXPLAIN statement.

Specified by:

getPlanSQL in interface Index

Overrides:

getPlanSQL in class BaseIndex

Returns:

the plan

canScan

public boolean canScan()

Description copied from interface: Index

Can this index iterate over all rows?

Specified by:

canScan in interface Index

Overrides:

canScan in class BaseIndex

Returns:

true if it can