DOCSP-45005: Specify Docs to Return

source/fundamentals/crud/read-operations.txt

@@ -13,7 +13,9 @@ Read Operations
    Retrieve Data </fundamentals/crud/read-operations/retrieve>
    Count Documents </fundamentals/crud/read-operations/count>
    Monitor Data Changes </fundamentals/crud/read-operations/change-streams>
+   /fundamentals/crud/read-operations/specify-documents-to-return
 
 - :ref:`csharp-retrieve`
 - :ref:`csharp-count-documents`
 - :ref:`csharp-change-streams`
+- :ref:`csharp-specify-documents-to-return`

source/fundamentals/crud/read-operations/specify-documents-to-return.txt

@@ -0,0 +1,220 @@
+.. _csharp-specify-documents-to-return:
+
+===========================
+Specify Documents to Return
+===========================
+
+.. contents:: On this page
+   :local:
+   :backlinks: none
+   :depth: 2
+   :class: singlecol
+
+.. facet::
+   :name: genre
+   :values: reference
+
+.. meta::
+   :keywords: read, paginate, pagination, order, code example
+
+Overview
+--------
+
+In this guide, you can learn how to specify which documents to return
+from a read operation by chaining the following methods to the ``Find()``
+method:
+
+- :ref:`Limit() <csharp-return-documents-limit>`: Specifies the maximum number of documents
+  to return from a query
+- :ref:`Sort() <csharp-return-documents-sort>`: Specifies the sort order for the returned documents
+- :ref:`Skip() <csharp-return-documents-skip>`: Specifies the number of documents to skip before
+  returning query results
+
+Sample Data
+~~~~~~~~~~~
+
+The examples in this guide use the ``restaurants`` collection in the ``sample_restaurants``
+database from the :atlas:`Atlas sample datasets </sample-data>`. To learn how to create a free MongoDB Atlas cluster and load the sample datasets, see the
+:atlas:`Get Started with Atlas </getting-started>` guide.
+
+The examples on this page use the following ``Restaurant`` class as a model for the
+documents in the collection:
+
+.. literalinclude:: /includes/fundamentals/code-examples/LimitSortSkip.cs
+   :start-after: start-restaurant-class
+   :end-before: end-restaurant-class
+   :language: csharp
+
+.. _csharp-return-documents-limit:
+
+Limit
+-----
+
+To specify the maximum number of documents returned from a read operation, use
+the ``Limit()`` method provided by the ``IFindFluent`` interface. After calling
+the ``Find()`` method, chain the ``Limit()`` method to modify the behavior of the
+operation.
+
+The following example finds all restaurants that have a ``cuisine`` field value
+of ``"Italian"`` and limits the results to ``5`` documents:
+
+.. io-code-block::
+   :copyable:
+
+   .. input:: /includes/fundamentals/code-examples/LimitSortSkip.cs
+      :start-after: start-limit
+      :end-before: end-limit
+      :language: csharp
+      :dedent:
+
+   .. output::
+      :visible: false
+
+      V & T Restaurant
+      Mimis Restaurant & Bar
+      Venice Restaurant
+      Areo Restaurant
+      Tre Giovani Pizza & Pasta
+
+.. tip::
+
+   The preceding example returns the first five documents matched by the query
+   according to their :manual:`natural order </reference/glossary/#std-term-natural-order>`
+   in the database. The following section describes how to return the documents
+   in a specified order.
+
+.. _csharp-return-documents-sort:
+
+Sort
+----
+
+To return documents in a specified order, use the ``Sort()`` method provided by
+the ``IFindFluent`` interface. After calling the ``Find()`` method, chain the ``Sort()``
+method to modify the behavior of the operation.
+
+When calling ``Sort()``, you must pass in the sort definition as a parameter. You can construct a sort
+definition by using the  ``Builders<T>.Sort.Ascending()`` method to sort values from
+lowest to highest, or the ``Builders<T>.Sort.Ascending()`` method to sort them from highest
+to lowest. Both of these methods take the field name to sort by as a parameter. These methods
+can be chained to sort returned documents by multiple fields.
+
+The following example returns all documents that have a ``cuisine`` field value
+of ``"Italian"``, sorted in ascending order of ``name`` field values:
+
+.. io-code-block::
+   :copyable:
+
+   .. input:: /includes/fundamentals/code-examples/LimitSortSkip.cs
+      :start-after: start-sort
+      :end-before: end-sort
+      :language: csharp
+      :dedent:
+
+   .. output::
+      :visible: false
+
+      (Lewis Drug Store) Locanda Vini E Olii
+      101 Restaurant And Bar
+      44 Sw Ristorante & Bar
+      900 Park
+      A Voce
+      ...
+
+.. _csharp-return-documents-skip:
+
+Skip
+----
+
+To skip a specified number of documents before returning your query results, use
+the ``Skip()`` method provided by the ``IFindFluent`` interface. After calling
+the ``Find()`` method, chain the ``Skip()`` method to modify the behavior of the
+operation.
+
+The following example returns all documents that have a ``cuisine`` field value
+of ``"Italian"`` and skips the first ``10`` documents:
+
+.. io-code-block::
+   :copyable:
+
+   .. input:: /includes/fundamentals/code-examples/LimitSortSkip.cs
+      :start-after: start-skip
+      :end-before: end-skip
+      :language: csharp
+      :dedent:
+
+   .. output::
+      :visible: false
+
+      Trattoria Alba
+      Da Umberto Restaurant
+      La Strada Restaurant
+      Pasta Lovers Trattoria
+      Nanni Restaurant
+      Villa Mosconi Restaurant
+      Villa Berulia
+      Marco Polo Ristorante
+      Cafe Luna
+      Baraonda
+
+.. _csharp-return-documents-combine:
+
+Combine Limit, Sort, and Skip
+-----------------------------
+
+You can chain the ``Limit()``, ``Sort()``, and ``Skip()`` methods to a single
+``Find()`` method call. This allows you to set a maximum number of sorted documents
+to return from the read operation, skipping a specified number of documents before
+returning.
+
+The following example returns ``5`` documents that have a ``cuisine`` value of
+``"Italian"``. The results are sorted in ascending order by the ``name`` field value,
+skipping the first ``10`` documents:
+
+.. io-code-block::
+   :copyable:
+
+   .. input:: /includes/fundamentals/code-examples/LimitSortSkip.cs
+      :start-after: start-limit-sort-skip
+      :end-before: end-limit-sort-skip
+      :language: csharp
+      :dedent:
+
+   .. output::
+      :visible: false
+
+      Acqua
+      Acqua Restaurant
+      Acqua Santa
+      Acquista Trattoria
+      Acquolina Catering
+      Adriatic Restaurant Pizzeria Bar
+      Adrienne'S Pizza Bar
+      Ai Fiori
+      Aita Restaurant
+      Al Di La
+
+.. note::
+
+   The order in which you call these methods doesn't change the documents
+   that are returned. The {+driver-short+} automatically reorders the calls to
+   perform the sort operation first, the skip operation next, and then the limit
+   operation.
+
+Additional Information
+----------------------
+
+For more information about retrieving documents, see the :ref:`csharp-retrieve` guide.
+
+For more information about specifying a query, see the :ref:`csharp-specify-query` guide.
+
+API Documentation
+~~~~~~~~~~~~~~~~~
+
+To learn more about any of the methods or types discussed in this
+guide, see the following API documentation:
+
+- `Find() <{+new-api-root+}/MongoDB.Driver/MongoDB.Driver.IMongoCollectionExtensions.Find.html>`_
+- `IFindFluent <{+new-api-root+}/MongoDB.Driver/MongoDB.Driver.IFindFluent-2.html>`_
+- `Limit() <{+new-api-root+}/MongoDB.Driver/MongoDB.Driver.IFindFluent-2.Limit.html>`_
+- `Sort() <{+new-api-root+}/MongoDB.Driver/MongoDB.Driver.IFindFluent-2.Sort.html>`_
+- `Skip() <{+new-api-root+}/MongoDB.Driver/MongoDB.Driver.IFindFluent-2.Skip.html>`_

source/includes/fundamentals/code-examples/LimitSortSkip.cs

@@ -0,0 +1,81 @@
+using MongoDB.Bson;
+using MongoDB.Bson.Serialization.Attributes;
+using MongoDB.Bson.Serialization.Conventions;
+using MongoDB.Driver;
+
+public class LimitSortSkip
+{
+    // Replace with your connection string
+    private const string MongoConnectionString = "<connection string URI>";
+
+    public static void Main(string[] args)
+    {   
+        var mongoClient = new MongoClient(MongoConnectionString);
+        var database = mongoClient.GetDatabase("sample_restaurants");
+        var collection = database.GetCollection<Restaurant>("restaurants");
+
+        {
+            // start-limit
+            var filter = Builders<Restaurant>.Filter.Eq("cuisine", "Italian");
+            var results = collection.Find(filter).Limit(5).ToList();
+
+            foreach (var result in results)
+            {
+                Console.WriteLine(result.Name);
+            }
+            // end-limit
+        }
+
+        {
+            // start-sort
+            var filter = Builders<Restaurant>.Filter.Eq("cuisine", "Italian");
+            var sort = Builders<Restaurant>.Sort.Ascending("name");
+            var results = collection.Find(filter).Sort(sort).ToList();
+
+            foreach (var result in results)
+            {
+                Console.WriteLine(result.Name);
+            }
+            // end-sort
+        }
+
+        {
+            // start-skip
+            var filter = Builders<Restaurant>.Filter.Eq("cuisine", "Italian");
+            var results = collection.Find(filter).Skip(10).ToList();
+
+            foreach (var result in results)
+            {
+                Console.WriteLine(result.Name);
+            }
+            // end-skip
+        }
+
+        {
+            // start-limit-sort-skip
+            var filter = Builders<Restaurant>.Filter.Eq("cuisine", "Italian");
+            var sort = Builders<Restaurant>.Sort.Ascending("name");
+
+            var results = collection.Find(filter).Limit(10).Sort(sort).Skip(10).ToList();
+
+            foreach (var result in results)
+            {
+                Console.WriteLine(result.Name);
+            }
+            // end-limit-sort-skip
+        }
+    }
+}
+
+// start-restaurant-class
+[BsonIgnoreExtraElements]
+public class Restaurant {
+    public ObjectId Id { get; set; }
+
+    [BsonElement("name")]
+    public string Name { get; set; }
+
+    [BsonElement("cuisine")]
+    public string Cuisine { get; set; }
+}
+// end-restaurant-class