Oracle Internal Arch. (contd.)
- temporary tables / indexes : Theses are kept in temporary segments. Here, space is allocated when rows are added to tables (different from permanent tables which have storage parameters).
- indexed segments : These are based on balanced B*-tree index where a leaf contains ROWIDs of datablocks that contain the required data.
- reverse key index : This is an index on reverse-keys. It is good when new keys are in ascending order. This balances insert/delete in all parts of tree. However, sequential scan capability is lost since continuous key data is no longer stored adjacent to each other in the index.