In most respects, a join index is similar to a base table. For example, you can do the following things to a join index:
- Create nonunique secondary indexes on its columns.
- Create a unique primary index on its columns, provided it is a non-compressed and nonvalue-ordered single-table join index.
- Execute COLLECT STATISTICS, DROP STATISTICS, HELP, and SHOW statements.
- Partition its primary index, if it is a noncompressed join index.
Unlike base tables, you cannot do the following things with join indexes:
- Query or update join index rows explicitly.
- Store and maintain arbitrary query results such as expressions.You can maintain aggregates or sparse indexes if you define the join index to do so.