title: Dropping a table in Oracle SQL
body: <p>Whenever I try to drop a table or create a table it is showing these errors:</p>
  
  <pre><code>DROP TABLE SUBURB;
  DROP TABLE STOCKITEM;
  DROP TABLE MANUFACTURER;
  DROP TABLE WAREHOUSE;
  DROP TABLE CITY;
  DROP TABLE STATE;
  </code></pre>
  
  <blockquote>
    <p>Error at line 1: ORA-02449: unique/primary keys in table referenced
    by foreign keys</p>
  </blockquote>
  
  <pre><code> CREATE TABLE STATE (
   statecode varchar(3)
   ,statename varchar(30)
   ,population number(8)
   ,primary key(statecode)
    );
  </code></pre>
  
  <blockquote>
    <p>Error at line 1: ORA-00955: name is already used by an existing object</p>
  </blockquote>
  
  <p>Can anybody explain why this happens?</p>