Apache Derby Database Engine and Embedded JDBC Driver 10.17.1.0 · org.apache.derby.iapi.store.raw.FetchDescriptor

FetchDescriptor is used to package up all the arguments necessary to describe what rows and what row parts should be returned from the store back to language as part of a fetch.

The FetchDescriptor may also contain scratch space used to process the qualifiers passed in the scan. This scratch space will be used to cache information about the qualifiers, valid column list, row size so that calculations need only be done once per scan rather than every iteration.

Field Summary

Modifier and Type	Field and Description
private int[]	materialized_cols
private int	maxFetchColumnId
private Qualifier[][]	qualifier_list
private int	row_length Fields of the class
private FormatableBitSet	validColumns
private int[]	validColumnsArray
private static final int[]	zero_fill_array
private static final int	ZERO_FILL_LENGTH

Constructor Summary

Access	Constructor and Description
pack-priv	FetchDescriptor() Constructors for This class:
public	FetchDescriptor(int input_row_length)
public	FetchDescriptor(int input_row_length, int single_valid_column_number)
public	FetchDescriptor(int input_row_length, FormatableBitSet input_validColumns, Qualifier[][] input_qualifier_list)

Method Summary

Modifier and Type	Method and Description
public final int[]	getMaterializedColumns() Internal to store.
public final int	getMaxFetchColumnId() Internal to store.
public final Qualifier[][]	Returns: The qualifier array, it may be null. getQualifierList() Return the qualifier array.
public final FormatableBitSet	Returns: The column list bit map. getValidColumns() Return the column list bit map.
public final int[]	getValidColumnsArray()
public final void	reset() Internal to store.
private final void	setMaxFetchColumnId()
public final void	setValidColumns(FormatableBitSet input_validColumns)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

materialized_cols	back to summary
private int[] materialized_cols

maxFetchColumnId	back to summary
private int maxFetchColumnId

qualifier_list	back to summary
private Qualifier[][] qualifier_list

row_length	back to summary
private int row_length Fields of the class

validColumns	back to summary
private FormatableBitSet validColumns

validColumnsArray	back to summary
private int[] validColumnsArray

zero_fill_array	back to summary
private static final int[] zero_fill_array

ZERO_FILL_LENGTH	back to summary
private static final int ZERO_FILL_LENGTH

Constructor Detail

FetchDescriptor	back to summary
pack-priv FetchDescriptor() Constructors for This class:

FetchDescriptor	back to summary
public FetchDescriptor(int input_row_length)

FetchDescriptor	back to summary
public FetchDescriptor(int input_row_length, int single_valid_column_number)

FetchDescriptor	back to summary
public FetchDescriptor(int input_row_length, FormatableBitSet input_validColumns, Qualifier[][] input_qualifier_list)

Method Detail

getMaterializedColumns	back to summary
public final int[] getMaterializedColumns() Internal to store.

getMaxFetchColumnId	back to summary
public final int getMaxFetchColumnId() Internal to store.

getQualifierList	back to summary
public final Qualifier[][] getQualifierList() Return the qualifier array. Return the array of qualifiers in this FetchDescriptor. The array of qualifiers which, applied to each key, restricts the rows returned by the scan. Rows for which any one of the qualifiers returns false are not returned by the scan. If null, all rows are returned. Qualifiers can only reference columns which are included in the scanColumnList. The column id that a qualifier returns in the column id the table, not the column id in the partial row being returned. A null qualifier array means there are no qualifiers. Returns:Qualifier[][] The qualifier array, it may be null.

getQualifierList

back to summary

public final Qualifier[][] getQualifierList()

Return the qualifier array.

Return the array of qualifiers in this FetchDescriptor. The array of qualifiers which, applied to each key, restricts the rows returned by the scan. Rows for which any one of the qualifiers returns false are not returned by the scan. If null, all rows are returned. Qualifiers can only reference columns which are included in the scanColumnList. The column id that a qualifier returns in the column id the table, not the column id in the partial row being returned.

A null qualifier array means there are no qualifiers.

Returns:Qualifier[][]: The qualifier array, it may be null.

getValidColumns	back to summary
public final FormatableBitSet getValidColumns() Return the column list bit map. A description of which columns to return from every fetch in the scan. A row array and a valid column bit map work together to describe the row to be returned by the scan - see RowUtil for description of how these two parameters work together to describe a "row". Returns:FormatableBitSet The column list bit map.

getValidColumns

back to summary

public final FormatableBitSet getValidColumns()

Return the column list bit map.

A description of which columns to return from every fetch in the scan. A row array and a valid column bit map work together to describe the row to be returned by the scan - see RowUtil for description of how these two parameters work together to describe a "row".

Returns:FormatableBitSet: The column list bit map.

getValidColumnsArray	back to summary
public final int[] getValidColumnsArray()

reset	back to summary
public final void reset() Internal to store.

setMaxFetchColumnId	back to summary
private final void setMaxFetchColumnId()