src/Web2All/Table/Collection.class.php
public function setKey($key)
  {
    $this->key=$key;
    $this->is_assoc=(is_null($this->key) ? false : true);
  }
public function setKey($key)
  {
    $this->key=$key;
    $this->is_assoc=(is_null($this->key) ? false : true);
  }
Assign a key to the list.
If you do this before calling fetchData() then
this list will become associative.

The key should be the name of a property

@param string $key