Which two statements are true about sequences created in a single instance database? (Choose two.)

Question

Options

• ACURRVAL is used to refer to the last sequence number that has been generated
• BDELETE <sequencename> would remove a sequence from the database
• CThe numbers generated by a sequence can be used only for one table
• DWhen the MAXVALUE limit for a sequence is reached, you can increase the MAXVALUE limit by
• EWhen a database instance shuts down abnormally, the sequence numbers that have been

• A
  72% (18)
• B
  8% (2)
• C
  4% (1)
• E
  16% (4)

Explanation

Gaps in the Sequence Although sequence generators issue sequential numbers without gaps, this action occurs independent of a commit or rollback. Therefore, if you roll back a statement containing a sequence, the number is lost. Another event that can cause gaps in the sequence is a system crash. If the sequence caches values in memory, those values are lost if the system crashes. Because sequences are not tied directly to tables, the same sequence can be used for multiple tables. However, if you do so, each table can contain gaps in the sequential numbers. Modifying a Sequence If you reach the MAXVALUE limit for your sequence, no additional values from the sequence are allocated and you will receive an error indicating that the sequence exceeds the MAXVALUE. To continue to use the sequence, you can modify it by using the ALTER SEQUENCE statement To remove a sequence, use the DROP statement: DROP SEQUENCE dept_deptid_seq;

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