title: Not able to add a new column to the existing primary key
body: <p>I have a primary key PK1 for the table TABLE1. Need to add one more column to the existing primary key.
  I was tying the following alter script </p>
  
  <pre><code>ALTER TABLE TABLE1
  ADD CONSTRAINT "PRIMARYKEYS" PRIMARY KEY
  ("PK1",
  "PK2");
  
  Error report:
  SQL Error: ORA-02260: table can have only one primary key
  02260. 00000 -  "table can have only one primary key"
  *Cause:    Self-evident.
  *Action:   Remove the extra primary key.
  </code></pre>
  
  <p>How can I add one more column to the primary key, without affecting the data(data has been verified , there are no duplication.)</p>