How does Oracle ensure that there are no duplicate numbers generated?

Oracle can achieve unique numbering by using sequences. A sequence is an independent database object that can generate unique numerical sequences. The uniqueness of the numbers can be ensured by following these steps:

1. Create a sequence: Use the CREATE SEQUENCE statement to create a sequence object, and specify the starting value, increment, minimum and maximum values, and other parameters for the sequence.

CREATE SEQUENCE seq_name
START WITH start_value
INCREMENT BY increment_value
MINVALUE min_value
MAXVALUE max_value;

1. To obtain unique values using a sequence: Use the NEXTVAL function to call a sequence and retrieve the next unique value wherever needed.

SELECT seq_name.NEXTVAL FROM dual;

1. Serial numbers are used in the data table: Apply the acquired serial number to the data table that needs to ensure uniqueness.

INSERT INTO table_name (column1, column2, ...)
VALUES (seq_name.NEXTVAL, value1, value2, ...);

By using sequences, Oracle can ensure that each retrieved number is unique, preventing any duplication. It is important to note that sequences are associated with the database connection, so each number retrieved is independent for each database connection.