title: ORA-00955 "name is already used by an existing object"
body: <p>I need to modify an existing PK. Therefore I drop an recreate it.</p>
  
  <pre><code>ALTER TABLE B DROP CONSTRAINT PK_B;
  ALTER TABLE B ADD CONSTRAINT PK_B PRIMARY KEY ("TYP", "NR", "HH", "QUART");
  </code></pre>
  
  <p>Unfortunately the last Statement will give me an error ORA-00955</p>
  
  <p>If I create the PK constraint like it was defined originally with:</p>
  
  <pre><code>ALTER TABLE B ADD CONSTRAINT PK_B PRIMARY KEY ("TYP", "NR", "HH");
  </code></pre>
  
  <p>everything works fine.</p>