title: oracle issue with trigger and nextval
body: <p>I have a table called employees with the following data:</p>
  
  <pre><code>  Employee_ID     Employee_Salary       Employee_HireDate
    100              ----                  -----
    101              ----                  -----
  </code></pre>
  
  <p>Now I want to create a trigger that allows me to fetch the new employee_id and to increment it by one so it can be put in the table. I have found an example like this:</p>
  
  <pre><code> CREATE OR REPLACE TRIGGER employee_b
   BEFORE INSERT ON employee
   FOR EACH ROW
   DECLARE
        v_employee_id employee.employee_id%TYPE;
   BEGIN
         SELECT employee_ID_SEQ.NEXTVAL
         INTO v_employee_id
             FROM dual;
         :NEW.employee_id:=v_employee_id;
   END;
  </code></pre>
  
  <p>But the error that I get is:</p>
  
  <pre><code> ERROR at line 4: PL/SQL: ORA-02289: sequence does not exist
  </code></pre>
  
  <p>I want to use that trigger before an insert event like:</p>
  
  <pre><code> INSERT INTO employee(employee_salary,employee_hiredate) VALUES (-----,------)
  </code></pre>
  
  <p>Any help with this?
  Thanks</p>