As explained in the fundamental concepts, indexes provide for fast lookup and/or sorted retrieval of database objects based on some search criteria, and cursors provide the means for iterating through the result set of objects. The eXtremeDB User's Guide describes indexes and cursors in detail and the SDK samples
samples/native/core/05_indexes*demonstrate the powerful variety of eXtremeDB supported indexes. B-tree indexes are common to most database systems but many of the eXtremeDB indexes enable specialized capabilities, such as handling geospatial data (R-trees) or multi-dimensional data (KD-trees).