Circumstances When a Dbspace Cannot Be Skipped
- Referential constraint checking
When you want to delete a parent row, the child rows must also be available for deletion, and must exist in an available fragment.
When you want to insert a new child row, the parent row must be found in the available fragments.
- Updates
When you perform an update that moves a record from one fragment to another, both fragments must be available.
- Inserts
When you try to insert records in a expression-based fragmentation strategy and the dbspace is unavailable, an error is returned.
When you try to insert records in a round-robin fragment-based strategy, and a dbspace is down, the database server inserts the rows into any available dbspace.
When no dbspace is available, an error is returned.
- Indexing
When you perform updates that affect the index, such as when you insert or delete rows, or update an indexed column, the index must be available.
When you try to create an index, the dbspace you want to use must be available.
- Serial keys
The first fragment is used to store the current serial-key value internally. This is not visible to you except when the first fragment becomes unavailable and a new serial key value is required, which can happen during INSERT statements.