Ordering attributes within a node: Difference between revisions

Revision as of 11:58, 14 July 2008

ATK Howto: Ordering attributes within a node

Complexity: Basic
Author: Ivo Jansch <ivo@achievo.org>

Ordering attributes within a node

If you have an atkNode, attributes (i.e. database columns) appear in the order in which they are added via atkNode::add().

If you have an atkMetaNode (or derived class), fields appear in the order in which they appear in the database. To control the order in which attributes appear within a node (i.e. on a "page"), use atkMetaPolicy::setOrder(), atkMetaPolicy::setIncludes() or the $order argument to either atkMetaNode::add() or atkMetaPolicy::add().

For example:

public static function meta(atkMetaPolicy $policy) {
  $policy->add("invoice_start_date", "atkDateAttribute");
  $policy->add("invoice_end_date", "atkDateAttribute");

  $policy->setOrder(array(
    "invoice_start_date",
    "invoice_end_date"
  ));
}

(In the case of atkMetaNodes, the order in which attributes are added has no effect because they configure themselves via database metadata, and attributes are added to nodes before both the settings from atkMetaNode::meta() are applied, and the atkMetaNode::postMeta() method is run--"adding" an attribute via either of these methods reconfigures an existing attribute. Attributes will appear in the order in which they are added in a constructor, but this is discouraged.)

@@ Line 3: / Line 3: @@
 ==Ordering attributes within a node==
-By default, fields appear in the order in which they appear in the database.  To control the order in which attributes appear within a node (i.e. on a "page"), use <tt>atkMetaPolicy::setOrder()</tt>, <tt>atkMetaPolicy::setIncludes()</tt> or the <tt>$order</tt> argument to either <tt>atkMetaNode::add()</tt> or <tt>atkMetaPolicy::add()</tt>.
+If you have an <tt>atkNode</tt>, attributes (i.e. database columns) appear in the order in which they are added via <tt>atkNode::add()</tt>.
+If you have an <tt>atkMetaNode</tt> (or derived class), fields appear in the order in which they appear in the database. To control the order in which attributes appear within a node (i.e. on a "page"), use <tt>atkMetaPolicy::setOrder()</tt>, <tt>atkMetaPolicy::setIncludes()</tt> or the <tt>$order</tt> argument to either <tt>atkMetaNode::add()</tt> or <tt>atkMetaPolicy::add()</tt>.
 For example:
@@ Line 19: / Line 21: @@
 </syntaxhighlight>
-(The order in which fields are added has no effect because fields are added to nodes before both the settings from <tt>atkMetaNode::meta()</tt> are applied, and the <tt>atkMetaNode::postMeta()</tt> method is run--"adding" a field via either of these fields reconfigures an existing node.  Fields <em>will</em> appear in the order in which they are added in a constructor, but configuring nodes via a constructor is discouraged.)
+(In the case of <tt>atkMetaNodes</tt>, the order in which attributes are added has no effect because they configure themselves [[Using the atkMetaNode|via database metadata]], and attributes are added to nodes before both the settings from <tt>atkMetaNode::meta()</tt> are applied, and the <tt>atkMetaNode::postMeta()</tt> method is run--"adding" an attribute via either of these methods <em>reconfigures</em> an existing attribute.  Attributes <em>will</em> appear in the order in which they are added in a constructor, but this is discouraged.)