B-Tree index :- B-tree is a self-balancing tree data structure that keeps data sorted and allows searches, sequential access, insertions, and deletions in logarithmic time.
This index is default index in oracle, Good for high cardinality (not identical or unique values like usernames, user-ids)
Bitmap index:- Bitmap index is a special kind of database index that uses bitmaps.
Excellent in Data warehouse environments Good for low cardinality values ( Less repeated values ex: Gender)
Function Based index:- Function-based indexes allow you to create an index based on a function or expression.
Good for columns that have SQL functions applied to them. This can be used with either a B-tree or bitmap index.
Concatenate or Composite index: - A database composite index or multi-column index is an index that is based on several columns.
Reverse index:- A form of B-tree index; useful to balance I/O in an index that has many sequential inserts.
Descending Index:- A form of B-tree index; used with indexes where corresponding column values are sorted in a descending order (the default order is ascending).
Global Partitioned Index:- Global index across all partitions in a partitioned table or regular table. This can be a B-tree index type and can’t be a bitmap index type.
Local Partitioned Index:- Local index based on individual partitions in a partitioned table. This can be either a B-tree or bitmap index type.
This index is default index in oracle, Good for high cardinality (not identical or unique values like usernames, user-ids)
Bitmap index:- Bitmap index is a special kind of database index that uses bitmaps.
Excellent in Data warehouse environments Good for low cardinality values ( Less repeated values ex: Gender)
Function Based index:- Function-based indexes allow you to create an index based on a function or expression.
Good for columns that have SQL functions applied to them. This can be used with either a B-tree or bitmap index.
Concatenate or Composite index: - A database composite index or multi-column index is an index that is based on several columns.
Reverse index:- A form of B-tree index; useful to balance I/O in an index that has many sequential inserts.
Descending Index:- A form of B-tree index; used with indexes where corresponding column values are sorted in a descending order (the default order is ascending).
Global Partitioned Index:- Global index across all partitions in a partitioned table or regular table. This can be a B-tree index type and can’t be a bitmap index type.
Local Partitioned Index:- Local index based on individual partitions in a partitioned table. This can be either a B-tree or bitmap index type.
0 comments:
Post a Comment