MINVALUE FAQS

 1. What is MINVALUE in Oracle sequences?

• MINVALUE defines the minimum possible value that a sequence can generate in Oracle. It ensures that the sequence doesn't go below a specific threshold, which is useful for managing sequence values within a defined range.

2. Can I create a sequence without specifying MINVALUE?

• Yes, if you don’t specify MINVALUE, Oracle will automatically set a default value:
• For ascending sequences: MINVALUE defaults to 1.
• For descending sequences: MINVALUE defaults to -1.

3. What happens if a sequence reaches its MINVALUE?

• If the sequence reaches the MINVALUE, and the sequence is not set to cycle (i.e., no CYCLE option), Oracle will throw an error if you attempt to call NEXTVAL again.
• If the sequence is set to cycle, it will restart at the MAXVALUE (for ascending sequences) or wrap around as defined by the sequence.

4. Can I change the MINVALUE for an existing sequence?

• You cannot directly modify the MINVALUE using the ALTER SEQUENCE statement. If you need to change it, you must drop and recreate the sequence with the desired MINVALUE.

5. What happens if the MINVALUE is higher than the START WITH value?

• If you set the MINVALUE higher than the START WITH value, the sequence will still start at the START WITH value and increment until it reaches the MINVALUE. The sequence will not be able to generate values lower than the MINVALUE.

6. What is the default behavior of MINVALUE for an ascending sequence?

• For an ascending sequence, if you don’t specify a MINVALUE, the default is 1. The sequence will generate values starting from 1 and increasing by the specified increment, but it will not go below 1 unless you explicitly set a different minimum value.

7. Can MINVALUE be used with descending sequences?

• Yes, MINVALUE is used to define the smallest value that a descending sequence can generate. By default, the MINVALUE for a descending sequence is -1, and you can set it to any other value.

8. How does MINVALUE work with CYCLE?

• When a sequence is created with the CYCLE option, once it reaches the MINVALUE, it will wrap around and generate the next value based on the MAXVALUE or the starting point, instead of throwing an error.

9. Can I use MINVALUE to prevent a sequence from generating negative numbers?

• Yes, by setting MINVALUE to 0 or any positive value, you can ensure that the sequence will never generate negative numbers, especially for sequences representing non-negative values such as IDs or quantities.

10. Is it possible to set both MINVALUE and MAXVALUE for a sequence?

• Yes, you can set both MINVALUE and MAXVALUE to define the range within which the sequence can generate values. You can also combine them with the CYCLE option for a circular sequence.

11. What is the effect of setting a MINVALUE in a sequence for business applications?

• Setting MINVALUE in a sequence can help ensure that business rules are enforced, such as preventing sequence numbers from falling below a threshold or ensuring IDs or order numbers don’t become negative.

12. What is the default MINVALUE for a sequence that starts in reverse order (descending)?

• For descending sequences, the default MINVALUE is -1. This means that the sequence will generate values starting from -1 and decrementing by the specified increment.