org.h2.table
Class MetaTable

java.lang.Object
  extended by org.h2.engine.DbObjectBase
      extended by org.h2.schema.SchemaObjectBase
          extended by org.h2.table.Table
              extended by 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
static long ROW_COUNT_APPROXIMATION
          The approximate number of rows of a meta table.
 
Fields inherited from class org.h2.table.Table
columns, compareMode, memoryPerRow, 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
MetaTable(Schema schema, int id, int type)
          Create a new metadata table.
 
Method Summary
 Index addIndex(Session session, java.lang.String indexName, int indexId, IndexColumn[] cols, IndexType indexType, int headPos, java.lang.String comment)
          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.
 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.
 ObjectArray<Row> generateRows(Session session, SearchRow first, SearchRow last)
          Generate the data for the given metadata table using the given first and last row filters.
 java.lang.String getCreateSQL()
          Build a SQL statement to re-create this object.
 java.lang.String getDropSQL()
          Build a SQL statement to drop this object.
 ObjectArray<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.
 java.lang.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, checkColumnIsNotReferenced, checkDeadlock, compareTypeSave, findPrimaryKey, fireAfter, fireAfterRow, fireBefore, fireBeforeRow, fireRow, getBestPlanItem, getCheckForeignKeyConstraints, getChildren, getColumn, getColumn, getColumns, getCompareMode, getConstraints, getCreateSQLForCopy, getIndexForColumn, getOnCommitDrop, getOnCommitTruncate, getPrimaryKey, getTemplateRow, getTemplateSimpleRow, getType, isGlobalTemporary, isPersistData, isPersistIndexes, removeConstraint, removeIndex, removeIndexOrTransferOwnership, removeSequence, removeTrigger, rename, renameColumn, setCheckForeignKeyConstraints, setColumns, 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, getHeadPos, 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, getHeadPos, getId, getModificationId, getName, isTemporary, setComment, setModified, 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)
          throws java.sql.SQLException
Create a new metadata table.

Parameters:
schema - the schema
id - the object id
type - the meta table type
Throws:
java.sql.SQLException
Method Detail

getDropSQL

public java.lang.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 java.lang.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,
                      java.lang.String indexName,
                      int indexId,
                      IndexColumn[] cols,
                      IndexType indexType,
                      int headPos,
                      java.lang.String comment)
               throws java.sql.SQLException
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
headPos - the position of the head (if the index already exists)
comment - the comment
Returns:
the index
Throws:
java.sql.SQLException

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 ObjectArray<Row> generateRows(Session session,
                                     SearchRow first,
                                     SearchRow last)
                              throws java.sql.SQLException
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
Throws:
java.sql.SQLException

removeRow

public void removeRow(Session session,
                      Row row)
               throws java.sql.SQLException
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
Throws:
java.sql.SQLException

addRow

public void addRow(Session session,
                   Row row)
            throws java.sql.SQLException
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
Throws:
java.sql.SQLException - if a constraint was violated

removeChildrenAndResources

public void removeChildrenAndResources(Session session)
                                throws java.sql.SQLException
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
Throws:
java.sql.SQLException

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()
                 throws java.sql.SQLException
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
Throws:
java.sql.SQLException - if renaming is not allowed

checkSupportAlter

public void checkSupportAlter()
                       throws java.sql.SQLException
Description copied from class: Table
Check if this table supports ALTER TABLE.

Specified by:
checkSupportAlter in class Table
Throws:
java.sql.SQLException - if it is not supported

truncate

public void truncate(Session session)
              throws java.sql.SQLException
Description copied from class: Table
Remove all rows from the table and indexes.

Specified by:
truncate in class Table
Parameters:
session - the session
Throws:
java.sql.SQLException

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 java.lang.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 ObjectArray<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