title: SQL Foreign Key Array referencing non-array
body: <pre><code>CREATE TABLE orders (
     id          SERIAL PRIMARY KEY,
     productid   INTEGER[] NOT NULL,
     amount      INTEGER[] NOT NULL,
     totalprice   FLOAT NOT NULL,
     ordertime    TIMESTAMP NOT NULL,
     FOREIGN KEY (productid) REFERENCES products(id)
  );
  </code></pre>
  
  <p>I was trying to create a table to record orders. Since that one order may contain more than one product, I plan to use an array to record the productids of every product, same thing with amount. However when I want to make the productid a foreign key which references the id attribute of table product, I found that productid is an array but products(id) is just one number. How can I solve this to make every element of the productid array reference the products(id)?? I am using postgresql btw.</p>
  
  <p>Thx adhead!</p>