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Zend Framework 2 Documentation (Manual)

File: /_sources/tutorials/lucene.searching.txt

.. _learning.lucene.searching:

Searching
=========

Searching is performed by using the ``find()`` method:

.. _learning.lucene.searching.search-example:

.. rubric:: Searching through the index

.. code-block:: php
   :linenos:

   $hits = $index->find($query);

   foreach ($hits as $hit) {
       printf("%d %f %s\n", $hit->id, $hit->score, $hit->title);
   }

This example demonstrates the usage of two special search hit properties -``id`` and ``score``.

``id`` is an internal document identifier used within a Lucene index. It may be used for a variety of operations,
including deleting a document from the index:

.. _learning.lucene.searching.delete-example:

.. rubric:: Deleting an Indexed Document

.. code-block:: php
   :linenos:

   $index->delete($id);

Or retrieving the document from the index:

.. _learning.lucene.searching.retrieve-example:

.. rubric:: Retrieving an Indexed Document

.. code-block:: php
   :linenos:

   $doc = $index->getDocument($id);

.. note::

   **Internal Document Identifiers**

   Important note! Internal document identifiers may be changed by index optimization or the auto-optimization
   process, but it's never changed within a single script's execution unless the ``addDocument()`` (which may
   involve an auto-optimization procedure) or ``optimize()`` methods are called.

The ``score`` field is a hit score. Search results are ordered by score by default (best results returned first).

It's also possible to order result sets by specific field values. See the :ref:`Zend\Search\Lucene documentation
<zend.search.lucene.searching.sorting>` for more details about this possibility.

The example also demonstrates an ability to access stored fields (e.g., ``$hit->title``). At the first access to
any hit property other than ``id`` or ``score``, document stored fields are loaded, and the corresponding field
value is returned.

This causes an ambiguity for documents having their own ``id`` or ``score`` fields; as a result, it's not
recommended to use these field names within stored documents. Nevertheless, they still can be accessed via the
``getDocument()`` method:

.. _learning.lucene.searching.id-score-fields:

.. rubric:: Accessing the original document's "id" and "score" fields

.. code-block:: php
   :linenos:

   $id    = $hit->getDocument()->id;
   $score = $hit->getDocument()->score;