title: Need foreign key as array
body: <pre><code>CREATE TABLE test ( id int PRIMARY KEY , name );
  
  CREATE TABLE test1 ( id integer[] REFERENCES test , rollid int );
  </code></pre>
  
  <p>ERROR:  foreign key constraint "test3_id_fkey" cannot be implemented
  DETAIL:  Key columns "id" and "id" are of incompatible types: integer[] and integer.</p>
  
  <p>after that I try to another way also</p>
  
  <pre><code>CREATE TABLE test1 ( id integer[] , rollid int);
  
  ALTER TABLE test1 ADD CONSTRAINT foreignkeyarray FOREIGN KEY (id) REFERENCES test;
  </code></pre>
  
  <p>ERROR:  foreign key constraint "fkarray" cannot be implemented
  DETAIL:  Key columns "id" and "id" are of incompatible types: integer[] and integer.</p>
  
  <p>so I try create a foreign key array means it say error. please tell me anyone?</p>
  
  <p>postgresql version is 9.1.</p>