title: merge three odoo (postgreSQL) databases in one database
body: <p>I have 3 databases with:</p>
  
  <ul>
  <li>same tables  </li>
  <li>same schema</li>
  <li>different data</li>
  </ul>
  
  <p>I want to merge all the 3 databases into one database and I want the result database to be recognized by odoo.</p>
  
  <p>I think that to do that I have to copy data of each table from each databases into the target, but as you know odoo when store data,it use an autoincrement primary key for all the tables and, when I copy those tables I have to synchronize the ids of the foreign keys related to those tables, as I see this maybe the only problem I will face. </p>
  
  <p>So my request is: I need a tool to synchronize the foreign keys automatically after the data has been moved to the target database.</p>
  
  <p>(brief : suggest to me the shortest path to do the work).</p>