Package org.h2.index
Class DualIndex
java.lang.Object
org.h2.engine.DbObject
org.h2.schema.SchemaObject
org.h2.index.Index
org.h2.index.VirtualTableIndex
org.h2.index.DualIndex
- All Implemented Interfaces:
HasSQL
An index for the DUAL table.
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Field Summary
Fields inherited from class org.h2.index.Index
columnIds, columns, indexColumns, indexType, table, uniqueColumnColumn
Fields inherited from class org.h2.engine.DbObject
AGGREGATE, comment, COMMENT, CONSTANT, CONSTRAINT, database, DOMAIN, FUNCTION_ALIAS, INDEX, RIGHT, ROLE, SCHEMA, SEQUENCE, SETTING, SYNONYM, TABLE_OR_VIEW, trace, TRIGGER, USER
Fields inherited from interface org.h2.util.HasSQL
ADD_PLAN_INFORMATION, DEFAULT_SQL_FLAGS, NO_CASTS, QUOTE_ONLY_WHEN_REQUIRED, REPLACE_LOBS_FOR_TRACE, TRACE_SQL_FLAGS
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionboolean
Check if the index can directly look up the lowest or highest value of a column.find
(SessionLocal session, SearchRow first, SearchRow last) Find a row or a list of rows and create a cursor to iterate over the result.findFirstOrLast
(SessionLocal session, boolean first) Find the first (or last) value of this index.double
getCost
(SessionLocal session, int[] masks, TableFilter[] filters, int filter, SortOrder sortOrder, AllColumnsForPlan allColumnsSet) Estimate the cost to search for rows given the search mask.Construct the CREATE ...Get the message to show in a EXPLAIN statement.Methods inherited from class org.h2.index.VirtualTableIndex
add, checkRename, close, getRowCount, getRowCountApproximation, needRebuild, remove, remove, truncate
Methods inherited from class org.h2.index.Index
canFindNext, canScan, checkIndexColumnTypes, compareRows, findNext, getColumnIndex, getColumns, getCostRangeIndex, getCreateSQLForCopy, getDiskSpaceUsed, getDuplicateKeyException, getDuplicatePrimaryKeyMessage, getIndexColumns, getIndexType, getRow, getRowFactory, getTable, getType, getUniqueColumnCount, getUniqueRowFactory, isFindUsingFullTableScan, isFirstColumn, isHidden, isRowIdIndex, mayHaveNullDuplicates, removeChildrenAndResources, update
Methods inherited from class org.h2.schema.SchemaObject
getSchema, getSQL, getSQL
Methods inherited from class org.h2.engine.DbObject
getChildren, getComment, getCreateSQLForMeta, getDatabase, getDropSQL, 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.util.HasSQL
getTraceSQL
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Constructor Details
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DualIndex
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Method Details
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find
Description copied from class:Index
Find a row or a list of rows and create a cursor to iterate over the result. -
getCost
public double getCost(SessionLocal session, int[] masks, TableFilter[] filters, int filter, SortOrder sortOrder, AllColumnsForPlan allColumnsSet) Description copied from class: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.- Specified by:
getCost
in classIndex
- Parameters:
session
- the sessionmasks
- per-column comparison bit masks, null means 'always false', see constants in IndexConditionfilters
- all joined table filtersfilter
- the current table filter indexsortOrder
- the sort orderallColumnsSet
- the set of all columns- Returns:
- the estimated cost
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getCreateSQL
Description copied from class:DbObject
Construct the CREATE ... SQL statement for this object.- Overrides:
getCreateSQL
in classIndex
- Returns:
- the SQL statement
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canGetFirstOrLast
public boolean canGetFirstOrLast()Description copied from class:Index
Check if the index can directly look up the lowest or highest value of a column.- Overrides:
canGetFirstOrLast
in classIndex
- Returns:
- true if it can
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findFirstOrLast
Description copied from class:Index
Find the first (or last) value of this index. The cursor returned is positioned on the correct row, or on null if no row has been found.- Overrides:
findFirstOrLast
in classIndex
- Parameters:
session
- the sessionfirst
- true if the first (lowest for ascending indexes) or last value should be returned- Returns:
- a cursor (never null)
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getPlanSQL
Description copied from class:Index
Get the message to show in a EXPLAIN statement.- Overrides:
getPlanSQL
in classIndex
- Returns:
- the plan
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