code: def namedb_get_namespace_by_preorder_hash( cur, preorder_hash, include_history=True ):
      
  
      select_query = "SELECT * FROM namespaces WHERE preorder_hash = ?;"
      namespace_rows = namedb_query_execute( cur, select_query, (preorder_hash,))
  
      namespace_row = namespace_rows.fetchone()
      if namespace_row is None:
          # no such namespace 
          return None 
  
      namespace = {}
      namespace.update( namespace_row )
  
      if include_history:
          hist = namedb_get_history( cur, namespace['namespace_id'] )
          namespace['history'] = hist
  
      namespace = op_decanonicalize(op_get_opcode_name(namespace['op']), namespace)
      return namespace
docs: Get a namespace by its preorder hash (regardless of whether or not it was expired.)