title: Insert statement attempted to include a duplicate key
body: <p>Trying to run </p>
  
  <pre><code>INSERT INTO BOOKING_EXTRAS (BOOKING_ID, EXTRAS_, EXTRAS_PRICE) VALUES ('1','Phone call: 1.80','1.8');
  </code></pre>
  
  <p>in Oracle SQL Developer. Ive had it running but when I close it, then reopen it I get this error:</p>
  
  <pre><code>Error starting at line 1 in command:
  INSERT INTO BOOKING_EXTRAS (BOOKING_ID, EXTRAS_, EXTRAS_PRICE) VALUES ('1','Phone call: 1.80','1.8')
  Error report:
  SQL Error: ORA-00001: unique constraint (COURSEWORK_XE.BOOKING_EXTRAS_PK) violated
  00001. 00000 -  "unique constraint (%s.%s) violated"
  *Cause:    An UPDATE or INSERT statement attempted to insert a duplicate key.
         For Trusted Oracle configured in DBMS MAC mode, you may see
         this message if a duplicate entry exists at a different level.
  *Action:   Either remove the unique restriction or do not insert the key.
  </code></pre>
  
  <p>how would I fix this? Its happening to every table I run!</p>