NOCYCLE FAQS

 1. What does NOCYCLE mean in Oracle sequences?

• The NOCYCLE option ensures that once a sequence reaches its MAXVALUE (for ascending sequences) or MINVALUE (for descending sequences), it stops. No further values can be generated, and an error is raised when NEXTVAL is called.

2. What happens when a sequence with NOCYCLE reaches its limit?

• When the sequence reaches its defined boundary (either MAXVALUE or MINVALUE), it will stop. Any further attempts to retrieve values with NEXTVAL will result in an error (ORA-02287).

3. Is NOCYCLE the default behavior for sequences in Oracle?

• Yes, by default, sequences in Oracle are created with NOCYCLE. If you do not specify CYCLE, the sequence will automatically use NOCYCLE.

4. How do I create a sequence with NOCYCLE?

• You can create a sequence with NOCYCLE using the following syntax:

CREATE SEQUENCE sequence_name

  START WITH start_value

  INCREMENT BY increment_value

  MAXVALUE max_value

  NOCYCLE;

• This ensures that once the sequence reaches MAXVALUE, it will stop generating values.

5. Can I change a sequence from CYCLE to NOCYCLE after it is created?

• No, you cannot alter a sequence directly from CYCLE to NOCYCLE. To make this change, you would need to drop the sequence and recreate it with the desired option.

6. What happens if a sequence reaches MAXVALUE or MINVALUE with NOCYCLE?

• If a sequence with NOCYCLE reaches its MAXVALUE (for ascending sequences) or MINVALUE (for descending sequences), it will stop. Attempts to get the next value will raise an error (ORA-02287).

7. Can I use NOCYCLE with descending sequences?

• Yes, NOCYCLE can be used with both ascending and descending sequences. For descending sequences, once the sequence reaches MINVALUE, it will stop generating further values.

8. Is there an error when trying to fetch a value after the sequence stops with NOCYCLE?

• Yes, when the sequence has reached its limit and NOCYCLE is enabled, trying to fetch another value will result in an error: ORA-02287: sequence number is beyond MAXVALUE (or MINVALUE for descending sequences).

9. Can NOCYCLE be used for sequences with a large range of values?

• Yes, you can create sequences with a very large MAXVALUE and use NOCYCLE. The sequence will stop when it reaches the MAXVALUE, but it will work for as long as the range is within the limits of the sequence's datatype.

10. Does NOCYCLE work with CACHE in sequences?

• Yes, the NOCYCLE option works alongside the CACHE option. CACHE allows Oracle to pre-allocate sequence values in memory for faster access, while NOCYCLE ensures that the sequence will stop once it hits its boundary.

11. How do I handle errors when a sequence with NOCYCLE stops?

• You should handle the error ORA-02287 in your application logic when the sequence reaches its boundary. This could involve alerting the user or taking other corrective actions, such as creating a new sequence or manually managing the boundary condition.

12. Can NOCYCLE be used in applications where the sequence is used as a unique identifier?

• NOCYCLE is typically not used when a continuous, never-repeating sequence is required, as it will stop generating values once the limit is reached. If you need to ensure continuous unique identifiers, CYCLE may be more appropriate for automatic wrapping.