title: Unique Indexes with Oracle partitioned tables
body: <p>I have a table <code>Customer_Chronics</code> in Oracle 11g.
   The table has three key columns as shown below :</p>
  
  <ul>
  <li>branch_code</li>
  <li>customer_id</li>
  <li>period</li>
  </ul>
  
  <p>I have partitioned by table by list of <code>branch_code</code>, and now I'm having dilemma.  Which is better:</p>
  
  <ol>
  <li>Create unique index indexNumberOne on Customer_Chronics (PERIOD, CUSTOMER_ID);</li>
  <li>Create unique index indexNumberTwo on Customer_Chronics (branch_code, PERIOD, CUSTOMER_ID);</li>
  </ol>
  
  <p>The actual data must be unique by <code>period, customer_id</code>. If I put a unique index only on these two columns Oracle will check all partitions on the table when inserting new records?</p>