org.h2.table

Class MetaTable

java.lang.Object

org.h2.engine.DbObjectBase

org.h2.schema.SchemaObjectBase

org.h2.table.Table

org.h2.table.MetaTable

All Implemented Interfaces:

DbObject, SchemaObject

public class MetaTable
extends Table

This class is responsible to build the database meta data pseudo tables.

Field Summary

Fields

Modifier and Type	Field and Description
static long	ROW_COUNT_APPROXIMATION The approximate number of rows of a meta table.

Fields inherited from class org.h2.table.Table

columns, compareMode, EXTERNAL_TABLE_ENGINE, isHidden, SYSTEM_TABLE, TABLE, TABLE_LINK, TYPE_CACHED, TYPE_MEMORY, VIEW

Fields inherited from class org.h2.engine.DbObjectBase

comment, database, trace

Fields inherited from interface org.h2.engine.DbObject

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

Constructor Summary

Constructors

Constructor and Description
MetaTable(Schema schema, int id, int type) Create a new metadata table.

Method Summary

Methods

Modifier and Type	Method and Description
Index	addIndex(Session session, String indexName, int indexId, IndexColumn[] cols, IndexType indexType, boolean create, String indexComment) Create an index for this table
void	addRow(Session session, Row row) Add a row to the table and all indexes.
boolean	canDrop() Check if this table can be dropped.
boolean	canGetRowCount() Check if the row count can be retrieved quickly.
boolean	canReference() Check if this table can be referenced.
void	checkRename() Check if this object can be renamed.
void	checkSupportAlter() Check if this table supports ALTER TABLE.
void	close(Session session) Close the table object and flush changes.
ArrayList<Row>	generateRows(Session session, SearchRow first, SearchRow last) Generate the data for the given metadata table using the given first and last row filters.
String	getCreateSQL() Build a SQL statement to re-create this object.
String	getDropSQL() Build a SQL statement to drop this object.
ArrayList<Index>	getIndexes() Get all indexes for this table.
long	getMaxDataModificationId() Get the last data modification id.
static int	getMetaTableTypeCount() Get the number of meta table types.
long	getRowCount(Session session) Get the row count for this table.
long	getRowCountApproximation() Get the approximated row count for this table.
Index	getScanIndex(Session session) Get the scan index to iterate through all rows.
String	getTableType() Get the table type name
Index	getUniqueIndex() Get any unique index for this table if one exists.
boolean	isDeterministic() Check if the table is deterministic.
boolean	isLockedExclusively() Check if this table is locked exclusively.
void	lock(Session session, boolean exclusive, boolean force) Lock the table for the given session.
void	removeChildrenAndResources(Session session) Remove all dependent objects and free all resources (files, blocks in files) of this object.
void	removeRow(Session session, Row row) Remove a row from the table and all indexes.
void	truncate(Session session) Remove all rows from the table and indexes.
void	unlock(Session s) Release the lock for this session.

Methods inherited from class org.h2.table.Table

addConstraint, addDependencies, addSequence, addTrigger, addView, canTruncate, checkDeadlock, checkWritingAllowed, commit, compareTypeSave, doesColumnExist, dropSingleColumnConstraintsAndIndexes, findPrimaryKey, fire, fireAfterRow, fireBeforeRow, fireRow, getBestPlanItem, getCheckForeignKeyConstraints, getChildren, getColumn, getColumn, getColumns, getCompareMode, getConstraints, getCreateSQLForCopy, getDefaultValue, getIndexForColumn, getOnCommitDrop, getOnCommitTruncate, getPrimaryKey, getRowIdColumn, getTemplateRow, getTemplateSimpleRow, getType, getViews, hasSelectTrigger, isGlobalTemporary, isHidden, isLockedExclusivelyBy, isPersistData, isPersistIndexes, removeConstraint, removeIndex, removeIndexOrTransferOwnership, removeSequence, removeTrigger, removeView, rename, renameColumn, setCheckForeignKeyConstraints, setColumns, setHidden, setOnCommitDrop, setOnCommitTruncate, updateRows, validateConvertUpdateSequence

Methods inherited from class org.h2.schema.SchemaObjectBase

getSchema, getSQL, initSchemaObjectBase

Methods inherited from class org.h2.engine.DbObjectBase

getComment, getDatabase, getId, getModificationId, getName, initDbObjectBase, invalidate, isTemporary, 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.engine.DbObject

getComment, getDatabase, getId, getName, isTemporary, setComment, setTemporary

Field Detail

ROW_COUNT_APPROXIMATION

public static final long ROW_COUNT_APPROXIMATION

The approximate number of rows of a meta table.

See Also:

Constant Field Values

Constructor Detail

MetaTable

public MetaTable(Schema schema,
         int id,
         int type)

Create a new metadata table.

Parameters:

schema - the schema

id - the object id

type - the meta table type

Method Detail

getDropSQL

public String getDropSQL()

Description copied from class: DbObjectBase

Build a SQL statement to drop this object.

Specified by:

getDropSQL in interface DbObject

Specified by:

getDropSQL in class DbObjectBase

Returns:

the SQL statement

getCreateSQL

public String getCreateSQL()

Description copied from class: DbObjectBase

Build a SQL statement to re-create this object.

Specified by:

getCreateSQL in interface DbObject

Specified by:

getCreateSQL in class DbObjectBase

Returns:

the SQL statement

addIndex

public Index addIndex(Session session,
             String indexName,
             int indexId,
             IndexColumn[] cols,
             IndexType indexType,
             boolean create,
             String indexComment)

Description copied from class: Table

Create an index for this table

Specified by:

addIndex in class Table

Parameters:

session - the session

indexName - the name of the index

indexId - the id

cols - the index columns

indexType - the index type

create - whether this is a new index

indexComment - the comment

Returns:

the index

lock

public void lock(Session session,
        boolean exclusive,
        boolean force)

Description copied from class: Table

Lock the table for the given session. This method waits until the lock is granted.

Specified by:

lock in class Table

Parameters:

session - the session

exclusive - true for write locks, false for read locks

force - lock even in the MVCC mode

isLockedExclusively

public boolean isLockedExclusively()

Description copied from class: Table

Check if this table is locked exclusively.

Specified by:

isLockedExclusively in class Table

Returns:

true if it is.

generateRows

public ArrayList<Row> generateRows(Session session,
                          SearchRow first,
                          SearchRow last)

Generate the data for the given metadata table using the given first and last row filters.

Parameters:

session - the session

first - the first row to return

last - the last row to return

Returns:

the generated rows

removeRow

public void removeRow(Session session,
             Row row)

Description copied from class: Table

Remove a row from the table and all indexes.

Specified by:

removeRow in class Table

Parameters:

session - the session

row - the row

addRow

public void addRow(Session session,
          Row row)

Description copied from class: Table

Add a row to the table and all indexes.

Specified by:

addRow in class Table

Parameters:

session - the session

row - the row

removeChildrenAndResources

public void removeChildrenAndResources(Session session)

Description copied from class: DbObjectBase

Remove all dependent objects and free all resources (files, blocks in files) of this object.

Specified by:

removeChildrenAndResources in interface DbObject

Overrides:

removeChildrenAndResources in class Table

Parameters:

session - the session

close

public void close(Session session)

Description copied from class: Table

Close the table object and flush changes.

Specified by:

close in class Table

Parameters:

session - the session

unlock

public void unlock(Session s)

Description copied from class: Table

Release the lock for this session.

Specified by:

unlock in class Table

Parameters:

s - the session

checkRename

public void checkRename()

Description copied from class: DbObjectBase

Check if this object can be renamed. System objects may not be renamed.

Specified by:

checkRename in interface DbObject

Specified by:

checkRename in class DbObjectBase

checkSupportAlter

public void checkSupportAlter()

Description copied from class: Table

Check if this table supports ALTER TABLE.

Specified by:

checkSupportAlter in class Table

truncate

public void truncate(Session session)

Description copied from class: Table

Remove all rows from the table and indexes.

Specified by:

truncate in class Table

Parameters:

session - the session

getRowCount

public long getRowCount(Session session)

Description copied from class: Table

Get the row count for this table.

Specified by:

getRowCount in class Table

Parameters:

session - the session

Returns:

the row count

canGetRowCount

public boolean canGetRowCount()

Description copied from class: Table

Check if the row count can be retrieved quickly.

Specified by:

canGetRowCount in class Table

Returns:

true if it can

canDrop

public boolean canDrop()

Description copied from class: Table

Check if this table can be dropped.

Specified by:

canDrop in class Table

Returns:

true if it can

getTableType

public String getTableType()

Description copied from class: Table

Get the table type name

Specified by:

getTableType in class Table

Returns:

the table type name

getScanIndex

public Index getScanIndex(Session session)

Description copied from class: Table

Get the scan index to iterate through all rows.

Specified by:

getScanIndex in class Table

Parameters:

session - the session

Returns:

the index

getIndexes

public ArrayList<Index> getIndexes()

Description copied from class: Table

Get all indexes for this table.

Specified by:

getIndexes in class Table

Returns:

the list of indexes

getMaxDataModificationId

public long getMaxDataModificationId()

Description copied from class: Table

Get the last data modification id.

Specified by:

getMaxDataModificationId in class Table

Returns:

the modification id

getUniqueIndex

public Index getUniqueIndex()

Description copied from class: Table

Get any unique index for this table if one exists.

Specified by:

getUniqueIndex in class Table

Returns:

a unique index

getMetaTableTypeCount

public static int getMetaTableTypeCount()

Get the number of meta table types. Supported meta table types are 0 .. this value - 1.

Returns:

the number of meta table types

getRowCountApproximation

public long getRowCountApproximation()

Description copied from class: Table

Get the approximated row count for this table.

Specified by:

getRowCountApproximation in class Table

Returns:

the approximated row count

isDeterministic

public boolean isDeterministic()

Description copied from class: Table

Check if the table is deterministic.

Specified by:

isDeterministic in class Table

Returns:

true if it is

canReference

public boolean canReference()

Description copied from class: Table

Check if this table can be referenced.

Overrides:

canReference in class Table

Returns:

true if it can