Apache Derby Database Engine and Embedded JDBC Driver 10.17.1.0 · org.apache.derby.impl.sql.execute.ScanResultSet

Abstract ResultSet class for NoPutResultSets which contain a scan. Returns rows that may be a column sub-set of the rows in the underlying object to be scanned. If accessedCols is not null then a sub-set of columns will be fetched from the underlying object (usually into the candidate row object), then the returned rows will be a compacted form of that row, with the not-fetched columns moved out. If accessedCols is null then the full row will be returned.
Example: if accessedCols indicates that we want to retrieve columns 1 and 4, then candidate row will have space for 5 columns (because that's the size of the rows in the underlying object), but only cols "1" and "4" will have values:

    0    1    2    3    4
 [  - , COL1,  - ,  - , COL4 ]

Rows returned by this ScanResultSet will have the values:

    0     1
 [ COL1, COL4 ]

Field Summary

Modifier and Type	Field and Description
protected FormatableBitSet	accessedCols If not null indicates the subset of columns that need to be pulled from the underlying object to be scanned.
pack-priv final ExecRow	candidate The candidate row, matches the shape of the rows in the underlying object to be scanned.
protected boolean	fetchRowLocations true if the scan should pick up row locations
public String	indexName
pack-priv int	isolationLevel The scan isolation level.
private boolean	isolationLevelNeedsUpdate Tells whether the isolation level needs to be updated.
pack-priv int	lockMode The actual lock mode used.
pack-priv final ExecRowBuilder	resultRowBuilder Object used to create and reset the candidate row.
private final int	suppliedLockMode The lock mode supplied through the constructor.
private final boolean	tableLocked If true, the table is marked as table locked in SYS.SYSTABLES.
public String	tableName
private final boolean	unspecifiedIsolationLevel If true, the isolation level is unspecified and must be refreshed on each open.

Inherited from org.apache.derby.impl.sql.execute.NoPutResultSetImpl:: checkNullCols clonedExecRow cncLen resultSetNumber targetResultSet

Constructor Summary

Access Constructor and Description

Access	Constructor and Description
pack-priv	ScanResultSet(Activation the activation activation, int number of the result set (unique within statement) resultSetNumber, int identifier of saved object for row template resultRowTemplate, int lock mode (record or table) lockMode, boolean true if marked as table locked in SYS.SYSTABLES tableLocked, int language isolation level for the result set isolationLevel, int Identifier of saved object for accessedCols, -1 if need to fetch all columns. colRefItem, double estimated row count optimizerEstimatedRowCount, double estimated cost optimizerEstimatedCost) Construct a `ScanResultSet`.

pack-priv

ScanResultSet(Activation

the activation

activation, int

number of the result set (unique within statement)

resultSetNumber, int

identifier of saved object for row template

resultRowTemplate, int

lock mode (record or table)

lockMode, boolean

true if marked as table locked in SYS.SYSTABLES

tableLocked, int

language isolation level for the result set

isolationLevel, int

Identifier of saved object for accessedCols, -1 if need to fetch all columns.

colRefItem, double

estimated row count

optimizerEstimatedRowCount, double

estimated cost

optimizerEstimatedCost)

Construct a ScanResultSet.

Method Summary

Modifier and Type	Method and Description
pack-priv abstract boolean	canGetInstantaneousLocks() Can we get instantaneous locks when getting share row locks at READ COMMITTED.
public void	close() Overrides org.apache.derby.impl.sql.execute.NoPutResultSetImpl.close. Implements org.apache.derby.iapi.sql.ResultSet.close. Close the result set.
private int	Returns: lock mode getLockMode(int the (language) isolation level languageLevel) Get the lock mode based on the language isolation level.
public int	getScanIsolationLevel() Overrides org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl.getScanIsolationLevel. Implements org.apache.derby.iapi.sql.execute.NoPutResultSet.getScanIsolationLevel. Return the isolation level of the scan in the result set.
pack-priv void	initIsolationLevel() Initialize the isolation level and the lock mode.
protected void	setRowLocationsState() Determine whether this scan should return row locations
public Element	toXML(Element Node to put content into. parentNode, String Element tag for content tag) Overrides org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl.toXML. Implements org.apache.derby.iapi.sql.ResultSet.toXML. Produce an xml image of this ResultSet and its descendant ResultSets.
private int	Returns: store isolation level translateLanguageIsolationLevel(int language isolation level languageLevel) Translate isolation level from language to store.

Field Detail

accessedCols	back to summary
protected FormatableBitSet accessedCols If not null indicates the subset of columns that need to be pulled from the underlying object to be scanned. Set from the PreparedStatement's saved objects, if it exists.

candidate	back to summary
pack-priv final ExecRow candidate The candidate row, matches the shape of the rows in the underlying object to be scanned.

fetchRowLocations	back to summary
protected boolean fetchRowLocations true if the scan should pick up row locations

indexName	back to summary
public String indexName

isolationLevel	back to summary
pack-priv int isolationLevel The scan isolation level.

isolationLevelNeedsUpdate	back to summary
private boolean isolationLevelNeedsUpdate Tells whether the isolation level needs to be updated.

lockMode	back to summary
pack-priv int lockMode The actual lock mode used.

resultRowBuilder	back to summary
pack-priv final ExecRowBuilder resultRowBuilder Object used to create and reset the candidate row.

suppliedLockMode	back to summary
private final int suppliedLockMode The lock mode supplied through the constructor.

tableLocked	back to summary
private final boolean tableLocked If true, the table is marked as table locked in SYS.SYSTABLES.

tableName	back to summary
public String tableName

unspecifiedIsolationLevel	back to summary
private final boolean unspecifiedIsolationLevel If true, the isolation level is unspecified and must be refreshed on each open.

Constructor Detail

ScanResultSet back to summary

ScanResultSet	back to summary
pack-priv ScanResultSet(Activation activation, int resultSetNumber, int resultRowTemplate, int lockMode, boolean tableLocked, int isolationLevel, int colRefItem, double optimizerEstimatedRowCount, double optimizerEstimatedCost) throws StandardException Construct a `ScanResultSet`. Parameters activation:Activation the activation resultSetNumber:int number of the result set (unique within statement) resultRowTemplate:int identifier of saved object for row template lockMode:int lock mode (record or table) tableLocked:boolean true if marked as table locked in SYS.SYSTABLES isolationLevel:int language isolation level for the result set colRefItem:int Identifier of saved object for accessedCols, -1 if need to fetch all columns. optimizerEstimatedRowCount:double estimated row count optimizerEstimatedCost:double estimated cost

pack-priv ScanResultSet(Activation activation, int resultSetNumber, int resultRowTemplate, int lockMode, boolean tableLocked, int isolationLevel, int colRefItem, double optimizerEstimatedRowCount, double optimizerEstimatedCost) throws StandardException

Construct a ScanResultSet.

Parameters

activation:Activation: the activation
resultSetNumber:int: number of the result set (unique within statement)
resultRowTemplate:int: identifier of saved object for row template
lockMode:int: lock mode (record or table)
tableLocked:boolean: true if marked as table locked in SYS.SYSTABLES
isolationLevel:int: language isolation level for the result set
colRefItem:int: Identifier of saved object for accessedCols, -1 if need to fetch all columns.
optimizerEstimatedRowCount:double: estimated row count
optimizerEstimatedCost:double: estimated cost

Method Detail

canGetInstantaneousLocks	back to summary
pack-priv abstract boolean canGetInstantaneousLocks() Can we get instantaneous locks when getting share row locks at READ COMMITTED.

close	back to summary
public void close() throws StandardException Overrides org.apache.derby.impl.sql.execute.NoPutResultSetImpl.close. Implements org.apache.derby.iapi.sql.ResultSet.close. Close the result set. Exceptions StandardException: if an error occurs

back to summary

public void close() throws StandardException

Overrides org.apache.derby.impl.sql.execute.NoPutResultSetImpl.close.

Implements org.apache.derby.iapi.sql.ResultSet.close.

Close the result set.

Exceptions

StandardException:: if an error occurs

getLockMode	back to summary
private int getLockMode(int languageLevel) Get the lock mode based on the language isolation level. Always do row locking unless the isolation level is serializable or the table is marked as table locked. Parameters languageLevel:int the (language) isolation level Returns:int lock mode

getLockMode

back to summary

private int getLockMode(int languageLevel)

Get the lock mode based on the language isolation level. Always do row locking unless the isolation level is serializable or the table is marked as table locked.

Parameters

languageLevel:int: the (language) isolation level

Returns:int

lock mode

getScanIsolationLevel	back to summary
public int getScanIsolationLevel() Overrides org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl.getScanIsolationLevel. Implements org.apache.derby.iapi.sql.execute.NoPutResultSet.getScanIsolationLevel. Return the isolation level of the scan in the result set. Returns:int Doc from org.apache.derby.iapi.sql.execute.NoPutResultSet.getScanIsolationLevel. The isolation level of the scan (in TransactionController constants).

getScanIsolationLevel

back to summary

public int getScanIsolationLevel()

Overrides org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl.getScanIsolationLevel.

Implements org.apache.derby.iapi.sql.execute.NoPutResultSet.getScanIsolationLevel.

Return the isolation level of the scan in the result set.

Returns:int

Doc from org.apache.derby.iapi.sql.execute.NoPutResultSet.getScanIsolationLevel.

The isolation level of the scan (in TransactionController constants).

initIsolationLevel	back to summary
pack-priv void initIsolationLevel() Initialize the isolation level and the lock mode. If the result set was constructed with an explicit isolation level, or if the isolation level has already been initialized, this is a no-op. All sub-classes should invoke this method from their `openCore()` methods.

setRowLocationsState	back to summary
protected void setRowLocationsState() throws StandardException Determine whether this scan should return row locations

toXML	back to summary
public Element toXML(Element parentNode, String tag) throws Exception Overrides org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl.toXML. Implements org.apache.derby.iapi.sql.ResultSet.toXML. Doc from org.apache.derby.iapi.sql.ResultSet.toXML. Produce an xml image of this ResultSet and its descendant ResultSets. Appends an element to the parentNode and returns the appended element. Parameters parentNode:Element Node to put content into. tag:String Element tag for content Returns:Element the content as an element with the given tag name Exceptions Exception: on error

toXML

back to summary

public Element toXML(Element parentNode, String tag) throws Exception

Overrides org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl.toXML.

Implements org.apache.derby.iapi.sql.ResultSet.toXML.

Doc from org.apache.derby.iapi.sql.ResultSet.toXML.

Produce an xml image of this ResultSet and its descendant ResultSets. Appends an element to the parentNode and returns the appended element.

Parameters

parentNode:Element: Node to put content into.
tag:String: Element tag for content

Returns:Element

the content as an element with the given tag name

Exceptions

Exception:: on error

translateLanguageIsolationLevel	back to summary
private int translateLanguageIsolationLevel(int languageLevel) Translate isolation level from language to store. Parameters languageLevel:int language isolation level Returns:int store isolation level

translateLanguageIsolationLevel

back to summary

private int translateLanguageIsolationLevel(int languageLevel)

Translate isolation level from language to store.

Parameters

languageLevel:int: language isolation level

Returns:int

store isolation level

pack-priv abstract Class ScanResultSet

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail