title: NSArray of NSArray creation
body: <p>In my app I've to create a structure like this:</p>
  
  <pre><code>$arrProducts = array(
      array(
          “product_id” =&gt; “1”,
          “qty” =&gt; 2
                  "options" =&gt; array(         
                      optionId_1 =&gt; optionValue_1,
                      ...,
                      optionId_n =&gt; optionValue_n
                   )
  </code></pre>
  
  <p>I did this array of array so:</p>
  
  <pre><code>NSDictionary *dict = @{
         @"product_id" : productID,
         @"qty": self.qty
     };
  NSArray *array2 = @[dict];
  </code></pre>
  
  <p>This array should work with a Magento store, when I run the app it shows me this message:</p>
  
  <p><code>error cart_product.add: SQLSTATE[21000]: Cardinality violation: 1241 Operand should contain 1 column(s)</code></p>
  
  <p>I guess this problem, depends on how I create this array, but I'm not understanding what's wrong with this array, can you help me to fix it?</p>
  
  <p><strong>UPDATE:</strong></p>
  
  <p>The library I'm using to connect to Magento needs this structure:</p>
  
  <pre><code>[Magento call:@[@"customer.create", @{
       @"email": email,
       @"password": password,
       @"firstname": firstname,
       @"lastname": lastname,
       @"website_id": @1,
       @"store_id": Magento.service.storeID
  }] success:^(AFHTTPRequestOperation *operation, id responseObject) {
      Magento.service.customerID = responseObject;
      NSLog(@"signUp customerID = %@", Magento.service.customerID);
  } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
      NSLog(@"error %@", error.localizedDescription);
  }];
  </code></pre>
  
  <p>I will use it to add a product into a cart if you take a look in <a href="http://www.magentocommerce.com/api/soap/checkout/cartProduct/cart_product.add.html" rel="nofollow">Magento SOAP API to add a product to cart</a> you can see that in <code>php</code>they add product by using an array of an array. I need to replicate the same structure.</p>