com.sleepycat.db
Interface DbBtreeCompare
public interface DbBtreeCompare
An interface specifying a comparison function, which imposes a
total ordering on the keys in a Btree database.
Method Summary |
int |
compare(Db db,
Dbt dbt1,
Dbt dbt2)
The DbBtreeCompare interface is used by the Db.setBtreeCompare
method. |
compare
int compare(Db db,
Dbt dbt1,
Dbt dbt2)
- The DbBtreeCompare interface is used by the Db.setBtreeCompare
method.
- Parameters:
db
- the enclosing database handle.dbt1
- the Dbt
representing
the application supplied key.dbt2
- the Dbt
representing
the current tree's key.
- Returns:
- The bt_compare_fcn function must return an
integer value less than, equal to, or greater than zero if
the first key parameter is considered to be respectively
less than, equal to, or greater than the second key
parameter. In addition, the comparison function must cause
the keys in the database to be well-ordered . The
comparison function must correctly handle any key values
used by the application (possibly including zero-length
keys). In addition, when Btree key prefix comparison is
being performed (see
Db.setBtreePrefix
for more information), the comparison
routine may be passed a prefix of any database key. The
data and size fields of the Dbt
are the only fields that may be
used for the purposes of this comparison, and no
particular alignment of the memory to which by the data
field refers may be assumed.