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DOCS-674 tailable cursor final edit after scott - removing javascript example
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source/tutorial/create-tailable-cursor.txt

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@@ -170,82 +170,7 @@ The ``tail`` function performs the following actions:
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- Loop through the outer ``while (1)`` loop to re-query with the new query
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condition and repeat.
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JavaScript Example
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------------------
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.. seealso::
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The JavaScript example uses a tailable cursor to output the results
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from a query of a capped collection named ``myCappedCollection``. To
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periodically check for new data, the ``cursor->hasNext()`` statement is
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inside a loop:
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.. code-block:: javascript
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var coll = db.myCappedCollection;
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var startDoc = coll.find().hint( { '$natural': 1 } ).limit(1).next();
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var lastValue = startDoc['insertDate'];
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printjson(startDoc)
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while (1) {
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var cursor = coll.find( { 'insertDate' : { '$gt' : lastValue } } ).hint( { '$natural': 1 } );
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cursor.addOption( DBQuery.Option.tailable );
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cursor.addOption( DBQuery.Option.awaitData );
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while ( cursor.hasNext() ) {
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var doc = cursor.next();
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lastValue = doc['insertDate'];
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printjson(doc);
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}
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}
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The example performs the following actions:
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- Query the capped collection to access the first document inserted.
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The query uses the :method:`hint() <cursor.hint()>` method to ensure
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the use of the insertion order.
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- Initialize the ``lastValue`` variable to hold the last accessed value
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of the unindexed field ``insertDate``. Newly added documents contain
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increasing values for the ``insertDate`` field.
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- In an outer ``while (1)`` loop,
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- Query the capped collection for documents with the field
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``insertDate`` greater than the ``lastValue``. The query uses the
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:method:`hint() <cursor.hint()>` method to ensure that the
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insertion order is used.
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- Specify that the returned cursor should be a tailable cursor:
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.. code-block:: javascript
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cursor.addOption( DBQuery.Option.tailable );
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See your :doc:`driver documentation </applications/drivers>` for
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the driver-specific method to specify a tailable cursor.
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- Specify that the cursor should block for a few seconds to wait for
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data:
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.. code-block:: javascript
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cursor.addOption( DBQuery.Option.awaitData );
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See your :doc:`driver documentation </applications/drivers>` for
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the driver-specific method to specify that the cursor should wait
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for data.
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- In an inner ``while (cursor.hasNext())`` loop,
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- retrieve the document,
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- update the ``lastValue`` variable,
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- print the document,
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- and loop to recheck for more documents.
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- If there are no more documents, repeat the outer loop.
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`Detailed blog post on tailable cursor
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<http://shtylman.com/post/the-tail-of-mongodb>`_

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