IDENTITY is red underlined while trying to create a table in SQL

I’m a Java student and I was trying to create a table for my database web app project.

CREATE TABLE customer (
  customer_id int IDENTITY(1,1) PRIMARY KEY,
  first_name varchar(45),
  last_name varchar(45),
  email varchar(45),
 
  );

So I used IDENTITY(1,1) to get the id start from 1 and auto increment by 1. But IDENTITY is underlined and I do not know why. Also when I try to run the code I get this Output :

Error starting at line : 1 in command -
CREATE TABLE customer (
  customer_id int IDENTITY(1,1),
  first_name varchar(45),
  last_name varchar(45),
  email varchar(45),
 
  )
Error report -
ORA-00907: missing right parenthesis
00907. 00000 -  "missing right parenthesis"
*Cause:    
*Action:

Answer

You have multiple syntax errors. But the code you want is:

CREATE TABLE customers (
    customer_id INT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    first_name varchar2(45),
    last_name varchar2(45),
    email varchar2(45)
);

Notes:

• The syntax in Oracle is different from SQL Server. There are no arguments to IDENTITY and you want GENERATED ALWAYS AS for the column.
• Oracle prefers VARCHAR2() to VARCHAR().
• You have missing and extra commas.
• 45 characters seems too short for the columns, particularly the email.
• I prefer table names in the plural because they contain multiple copies of an entity.