DOCSP-13961: query operators fixes (#133)

* DOCSP-13961: query operators fixes

Author: Chris Cho

source/fundamentals/crud/query-document.txt

@@ -7,16 +7,16 @@ Specify a Query
 Overview
 ~~~~~~~~
 
-Most CRUD operations apply to a set of matched documents in a
-collection. By default, these operations match **all** documents in a
-collection. Sometimes, however, you want to match only certain items in
-a collection; the query document allows you to make your searches more
-specific. Query documents contain one or more field-level expressions
-that determine which documents to include in the result set. You can
-match fields against literal values (e.g. ``{title:'The Room'}``) or
-compose :manual:`query operators </reference/operator/query/>` to
-express more complex queries. MongoDB
-supports multiple types of query operator, including:
+Most CRUD operations allow you to narrow the set of matched documents by
+specifying matching criteria in a **query document**. Query documents contain
+one or more query operators that apply to specific fields which  determine which
+documents to include in the result set.
+
+In a query document, you can match fields against literal values
+(e.g. ``{ title: 'The Room' }``) or you can compose
+:manual:`query operators </reference/operator/query/>` to express more
+complex matching criteria. In this guide, we cover the following categories
+of query operators in MongoDB and show examples on how to use them:
 
 - :manual:`Comparison Operators </reference/operator/query-comparison/>`
 
@@ -26,9 +26,9 @@ supports multiple types of query operator, including:
 
 - :manual:`Evaluation Operators </reference/operator/query-evaluation/>`
 
-Consider a collection containing documents that describe an inventory of
-fruit. To insert this data into a collection, run the following
-operation:
+Use the following code snippet to create a collection of documents that
+describe an inventory of fruit to follow along with our query operator
+examples:
 
 .. code-block:: javascript
 
@@ -56,9 +56,10 @@ documents containing a field called "name" that has a value of "apples":
    const cursor = collection.find(query);
    await cursor.forEach(console.dir);
 
-This will print out the following results:
+This code snippet returns the following results:
 
 .. code-block:: javascript
+   :copyable: false
 
    { "_id": 1, "name": "apples", "qty": 5, "rating": 3 }
 
@@ -71,13 +72,13 @@ This will print out the following results:
 
       collection.find({
          rating: { $eq: 5 }
-      }
+      })
 
   .. code-block:: javascript
 
       collection.find({
          rating: 5
-      }
+      })
 
 Comparison Operators
 --------------------
@@ -96,9 +97,10 @@ documents with a quantity value greater than 5 and prints them out:
    const cursor = collection.find(query);
    await cursor.forEach(console.dir);
 
-This will print out the following results:
+This code snippet returns the following results:
 
 .. code-block:: javascript
+   :copyable: false
 
    { "_id": 2, "name": "bananas", "qty": 7, "rating": 1 }
    { "_id": 3, "name": "oranges", "qty": 6, "rating": 2 }
@@ -115,13 +117,14 @@ that is not greater than 5 and prints them out:
 
 .. code-block:: javascript
 
-   const query = { qty: { $not { { $gt : 5 } } };
+   const query = { qty: { $not: { $gt: 5 }}};
    const cursor = collection.find(query);
    await cursor.forEach(console.dir);
 
-This will print out the following results:
+This code snippet returns the following results:
 
 .. code-block:: javascript
+   :copyable: false
 
    { "_id": 4, "name": "avocados", "qty": 3, "rating": 5 }
    { "_id": 1, "name": "apples", "qty": 5, "rating": 3 }
@@ -138,7 +141,7 @@ This will print out the following results:
     collection.find({
       rating: { $eq: 5 },
       qty: { $gt: 4 }
-    }
+    })
 
   .. code-block:: javascript
 
@@ -147,7 +150,10 @@ This will print out the following results:
          rating: { $eq: 5 },
          qty: { $gt: 4 }
       ]
-    }
+    })
+
+For more information on comparison operators, see the reference manual
+entry for :manual:`Comparison Query Operators </reference/operator/query-comparison/>`.
 
 Element Operators
 -----------------
@@ -163,31 +169,40 @@ field:
    const cursor = collection.find(query);
    await cursor.forEach(console.dir);
 
-This will print out the following results:
+This code snippet returns the following results:
 
 .. code-block:: javascript
+   :copyable: false
 
    { "_id": 2, "name": "bananas", "qty": 7, "rating": 1, "microsieverts": 0.1 }
 
+For more information on this operator, see the reference manual entry for
+the :manual:`$exists operator </reference/operator/query/exists/>`.
+
 Evaluation Operators
 --------------------
 
 Evaluation operators allow you to execute higher level logic, like
 regex and text searches, when querying for documents in a collection.
 Common evaluation operators include ``$regex`` and ``$text``.
 The following operation uses the evaluation operator ``$mod`` to search
-for documents with a quantity value that is divisible by 3:
+for documents with a quantity value that is divisible by 3 with
+a remainder of 0:
 
 .. code-block:: javascript
 
    // $mod means "modulo" and returns the remainder after division
-   const query = { microsieverts: { $mod : 3, 0 } };
+   const query = { qty: { $mod: [ 3, 0 ] } };
    const cursor = collection.find(query);
    await cursor.forEach(console.dir);
 
-This will print out the following results:
+This code snippet returns the following results:
 
 .. code-block:: javascript
+   :copyable: false
 
    { "_id": 3, "name": "oranges", "qty": 6, "rating": 2 }
    { "_id": 4, "name": "avocados", "qty": 3, "rating": 5 }
+
+For more information on this operator, see the reference manual entry for
+the :manual:`$mod operator </reference/operator/query/mod/>`.