| org.apache.derby.catalog.IndexDescriptor
All known Subclasses: org.apache.derby.catalog.types.IndexDescriptorImpl, org.apache.derby.iapi.sql.dictionary.IndexRowGenerator,
| IndexDescriptor | | public interface IndexDescriptor (Code) | | This interface describes an index.
It is used in the column SYS.SYSCONGLOMERATES.DESCRIPTOR
and describes everything about an index except the index name and
the table on which the index is defined.
That information is available
in the columns NAME and TABLEID of the table SYS.SYSCONGLOMERATES.
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| Method Summary | |
| public int[] | baseColumnPositions()
Returns an array of column positions in the base table. | | public Integer | getKeyColumnPosition(Integer heapColumnPosition)
Returns the postion of a column. | | public int | getKeyColumnPosition(int heapColumnPosition)
Returns the postion of a column.
Returns the position of a column within the key (1-based).
0 means that the column is not in the key. | | String | indexType()
Returns the type of the index. | | public boolean[] | isAscending()
Returns array of boolean telling asc/desc info for each index
key column for convenience of using together with baseColumnPositions
method. | | boolean | isAscending(Integer keyColumnPosition)
Returns true if the specified column is ascending in the index
(1-based). | | boolean | isDescending(Integer keyColumnPosition)
Returns true if the specified column is descending in the index
(1-based). | | boolean | isUnique()
Returns true if the index is unique. | | int | numberOfOrderedColumns()
Returns the number of ordered columns. | | public void | setBaseColumnPositions(int[] baseColumnPositions)
set the baseColumnPositions field of the index descriptor. | | public void | setIsAscending(boolean[] isAscending)
set the isAscending field of the index descriptor. | | public void | setNumberOfOrderedColumns(int numberOfOrderedColumns)
set the numberOfOrderedColumns field of the index descriptor. |
| baseColumnPositions | | public int[] baseColumnPositions()(Code) | | Returns an array of column positions in the base table. Each index
column corresponds to a column position in the base table, except
the column representing the location of the row in the base table.
The returned array holds the column positions in the
base table, so, if entry 2 is the number 4, the second
column in the index is the fourth column in the table.
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| getKeyColumnPosition | | public Integer getKeyColumnPosition(Integer heapColumnPosition)(Code) | | Returns the postion of a column.
Returns the position of a column within the key (1-based).
0 means that the column is not in the key.
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| getKeyColumnPosition | | public int getKeyColumnPosition(int heapColumnPosition)(Code) | | Returns the postion of a column.
Returns the position of a column within the key (1-based).
0 means that the column is not in the key. Same as the above
method, but it uses int instead of Integer.
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| indexType | | String indexType()(Code) | | Returns the type of the index. For now, we only support B-Trees,
so the value "BTREE" is returned.
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| isAscending | | public boolean[] isAscending()(Code) | | Returns array of boolean telling asc/desc info for each index
key column for convenience of using together with baseColumnPositions
method. Both methods return an array with subscript starting from 0.
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| isAscending | | boolean isAscending(Integer keyColumnPosition)(Code) | | Returns true if the specified column is ascending in the index
(1-based).
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| isDescending | | boolean isDescending(Integer keyColumnPosition)(Code) | | Returns true if the specified column is descending in the index
(1-based). In the current release, only ascending columns are
supported.
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| isUnique | | boolean isUnique()(Code) | | Returns true if the index is unique.
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| numberOfOrderedColumns | | int numberOfOrderedColumns()(Code) | | Returns the number of ordered columns.
In the future, it will be
possible to store non-ordered columns in an index. These will be
useful for covered queries. The ordered columns will be at the
beginning of the index row, and they will be followed by the
non-ordered columns.
For now, all columns in an index must be ordered.
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| setBaseColumnPositions | | public void setBaseColumnPositions(int[] baseColumnPositions)(Code) | | set the baseColumnPositions field of the index descriptor. This
is for updating the field in operations such as "alter table drop
column" where baseColumnPositions is changed.
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| setIsAscending | | public void setIsAscending(boolean[] isAscending)(Code) | | set the isAscending field of the index descriptor. This
is for updating the field in operations such as "alter table drop
column" where isAscending is changed.
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| setNumberOfOrderedColumns | | public void setNumberOfOrderedColumns(int numberOfOrderedColumns)(Code) | | set the numberOfOrderedColumns field of the index descriptor. This
is for updating the field in operations such as "alter table drop
column" where numberOfOrderedColumns is changed.
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