如何在Oracle 12c中创建表

Question

我尝试在Oracle 12c中创建表失败，错误为ORA-02000：缺少（关键字 02000. 00000-“缺少％s关键字” 我在做什么错了？

CREATE TABLE sometable(
student_id NUMERIC GENERATED ALWAYS AS IDENTITY( START WITH 1 INCREMENT BY 1) 
NOT NULL,
full_name VARCHAR2(255) NOT NULL,    
email VARCHAR2(255) NOT NULL UNIQUE,    
gpa NUMBER(5,2) NOT NULL,    
pass VARCHAR2(255) NOT NULL,    
student_role NUMERIC NOT NULL,    
CONSTRAINT student_pk PRIMARY KEY(student_id)

);