Oracle sequence creation and function ____oracle

1. Create:

CREATE SEQUENCE emp_sequence  --sequence name
INCREMENT by 1-   -if omitted, the default is 1, and if negative, the value of the sequence is decremented by this step. Start 
with 1       -counting the Nomaxvalue from 1-        without setting the maximum nocycle-is               cumulative and does not cycle  
CACHE;  --cache (buffering) defines the size of the memory block that holds the sequence, and defaults to 20.

2. Modify:

ALTER SEQUENCE sequence name
[INCREMENT by n]
[{maxvalue/minvalue n| Nomaxvalue}]
[{cycle| Nocycle}]
[{CACHE n| NoCache}];

* Cannot modify the initial value of the sequence

3. Delete

DROP SEQUENCE sequence name;

4. View all sequences

Select Sequence_name from Dba_sequences

SELECT * FROM User_sequences

5. Features:

is a database object provided by Oacle to produce a series of unique numbers.

L provide a unique numeric value automatically

L Shared objects

L primarily used to provide primary key values

L Loading sequence values into memory can improve access efficiency