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Interface COM.cloudscape.types.IndexDescriptor
- public interface IndexDescriptor
- extends java.io.Serializable
Copyright © 1998-2000, Informix Software, Inc. All rights reserved.
This interface is used in the column SYS.SYSCONGLOMERATES.DESCRIPTOR.
It 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.
baseColumnPositions()
- Returns an array of column positions in the base table.
getKeyColumnPosition(int)
- Returns the position of a column within the key (1-based).
getKeyColumnPosition(Integer)
- Returns the position of a column within the key (1-based).
indexType()
- Returns the type of the index.
isAscending(Integer)
- Returns true if the specified column is ascending in the index
(1-based).
isDescending(Integer)
- Returns true if the specified column is descending in the index
(1-based).
isUnique()
- Returns true if the index is unique.
numberOfOrderedColumns()
- Returns the number of ordered columns.
isUnique
public boolean isUnique()
Returns true if the index is unique.
baseColumnPositions
public int[] baseColumnPositions()
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.
getKeyColumnPosition
public java.lang.Integer getKeyColumnPosition(java.lang.Integer heapColumnPosition)
Returns the position of a column within the key (1-based).
0 means that the column is not in the key.
getKeyColumnPosition
public int getKeyColumnPosition(int heapColumnPosition)
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.
numberOfOrderedColumns
public int numberOfOrderedColumns()
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.
indexType
public java.lang.String indexType()
Returns the type of the index. For now, we only support B-Trees,
so the value "BTREE" is returned.
isAscending
public boolean isAscending(java.lang.Integer keyColumnPosition)
Returns true if the specified column is ascending in the index
(1-based).
isDescending
public boolean isDescending(java.lang.Integer keyColumnPosition)
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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