title: Oracle table create error ORA-00904 invalid identifier
body: <p>It's very interesting I don't know why I'm getting ORA-00904 invalid identifier when I'm trying to create a table with oracle.</p>
  
  <pre><code>CREATE TABLE animals
  (
     CONSTRAINT animal_id NUMBER(6) PRIMARY_KEY,
     name VARCHAR2(25),
     CONSTRAINT license_tag_number NUMBER(10) UNIQUE,
     admit_date DATE NOT NULL,
     adoption_id NUMBER(5),
     vaccination_date DATE NOT NULL
  );
  </code></pre>