What are the differences between Oracle composite index…
Composite index refers to creating indexes on multiple columns in a table, whereas a single index refers to creating an index on only one column.
The differences are as follows:
- Composite index can improve query efficiency by simultaneously querying multiple columns, while a single index can only improve query efficiency by querying one column.
- Composite indexes can decrease the number of indexes, reduce storage space, and improve the performance of insertions, updates, and deletions. In contrast, individual indexes require more storage space and may impact the performance of insertions, updates, and deletions.
- The selectivity of composite indexes may decrease as combining multiple columns can lower the selectivity of the index, while a single index can have higher selectivity.
- Composite indexes are effective only when all columns of the composite index are used in the query, while a single index can be effective even when only the indexed column is used.
- Combining indexes can provide better performance optimization for queries involving multiple columns, whereas a single index can only optimize performance for queries on a single column. In summary, composite indexes are suitable for multi-column queries, improving query efficiency and performance, while single indexes are suitable for single-column queries, enhancing query efficiency and performance. When choosing between composite and single indexes, it is important to consider the specific query scenarios and requirements for a balanced decision.
