Creating a resource in Zend_Acl is very simple. Zend_Acl provides the resource, Zend_Acl_Resource_Interface, to facilitate creating resources in an application. A class need only implement this interface, which consists of a single method, getResourceId(), for Zend_Acl to recognize the object as a resource. Additionally, Zend_Acl_Resource is provided by Zend_Acl as a basic resource implementation for developers to extend as needed.

Zend_Acl provides a tree structure to which multiple resources can be added. Since resources are stored in such a tree structure, they can be organized from the general (toward the tree root) to the specific (toward the tree leaves). Queries on a specific resource will automatically search the resource's hierarchy for rules assigned to ancestor resources, allowing for simple inheritance of rules. For example, if a default rule is to be applied to each building in a city, one would simply assign the rule to the city, instead of assigning the same rule to each building. Some buildings may require exceptions to such a rule, however, and this can be achieved in Zend_Acl by assigning such exception rules to each building that requires such an exception. A resource may inherit from only one parent resource, though this parent resource can have its own parent resource, etc.

Zend_Acl also supports privileges on resources (e.g., "create", "read", "update", "delete"), so the developer can assign rules that affect all privileges or specific privileges on one or more resources.