DOCS-14277 sparse and non sparse updates (#679)

* DOCS-14277 sparse and non sparse updates

* update examples

* add Unique to header

* usage -> creation

* remove unlike other indexes from extract

* CR1

* CR 1.5

* CR 2

* update collection name

* TR Comments 1

* TR 1.5 Adding basic and unique section

* add periods to bullets

* remove bullet points

* patten -> pattern

Author: ianf-mongodb

source/core/index-sparse.txt

@@ -100,6 +100,8 @@ index keys along with ascending/descending index keys, only the
 existence of the ``text`` index field(s) determine whether the index
 references a document.
 
+.. _sparse-unique-index:
+
 ``sparse`` and ``unique`` Properties
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -249,3 +251,9 @@ and ``90``:
       { "userid": "BBBBBBB", "score": 90 }
    ] )
 
+.. _sparse-and-non-sparse_example:
+
+Sparse and Non-Sparse Unique Indexes
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. include:: /includes/fact-5.0-sparse-unique-index-updates.rst

source/core/index-unique.txt

@@ -284,3 +284,45 @@ The unique index constraints mean that:
 
 - For an already-sharded collection, you cannot create unique indexes
   on other fields.
+
+Sparse and Non-Sparse Unique Indexes
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. include:: /includes/fact-5.0-sparse-unique-index-updates.rst
+
+Basic and Unique Indexes With Duplicate Key Patterns
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Starting in MongoDB 5.0, basic and unique indexes can exist with the
+same :ref:`key pattern <key_patterns>`. 
+
+This duplication in key patterns allows for adding a unique index to 
+already indexed fields.
+
+In this example:
+
+Create a basic index with the key pattern ``{ score : 1 }`` and insert 
+three documents.
+
+.. code-block:: javascript
+
+   db.scoreHistory.createIndex( { score : 1 }, { name: "basic_index" } )
+   db.scoreHistory.insert( { score : 1 } )
+   db.scoreHistory.insert( { score : 2 } )
+   db.scoreHistory.insert( { score : 3 } )
+
+Create a unique index with the same key pattern ``{ score : 1 }``.
+
+.. code-block:: javascript
+
+   db.scoreHistory.createIndex( { score : 1 }, { name: "unique_index", unique: true } )
+
+Try to insert a duplicate ``score`` document that fails because of
+the unique index.
+
+.. code-block:: javascript
+
+   db.scoreHistory.insert( { score : 3 } )
+
+
+

source/includes/extracts-collation.yaml

@@ -81,9 +81,9 @@ content: |
 ---
 ref: collation-index-options
 content: |
-   Unlike other index options, you can create multiple indexes on the same
-   key(s) with different collations. To create indexes with the same key
-   pattern but different collations, you must supply unique index names.
+   You can create multiple indexes on the same key(s) with different 
+   collations. To create indexes with the same key pattern but different
+   collations, you must supply unique index names.
 ---
 ref: collation-index-collection
 content: |-

source/includes/fact-5.0-sparse-unique-index-updates.rst

@@ -0,0 +1,25 @@
+Starting in MongoDB 5.0, :ref:`unique sparse <sparse-unique-index>` 
+and :ref:`unique non-sparse <unique-index>` indexes with the same 
+:ref:`key pattern<key_patterns>` can exist on a single collection.
+
+Unique and Sparse Index Creation
+````````````````````````````````
+
+This example creates multiple indexes with the same key pattern and 
+different ``sparse`` options:
+
+.. code-block:: javascript
+
+   db.scoreHistory.createIndex( { score : 1 }, { name: "unique_index", unique: true } )
+   db.scoreHistory.createIndex( { score : 1 }, { name: "unique_sparse_index", unique: true, sparse: true } )
+
+Basic and Sparse Index Creation
+```````````````````````````````
+
+You can also create basic indexes with the same key pattern with and 
+without the sparse option:
+
+.. code-block:: javascript
+
+   db.scoreHistory.createIndex( { score : 1 }, { name: "sparse_index", sparse: true } )
+   db.scoreHistory.createIndex( { score : 1 }, { name: "basic_index" } )

source/reference/command/createIndexes.txt

@@ -630,22 +630,20 @@ Memory Usage Limit
 Index Options
 ~~~~~~~~~~~~~
 
-Non-Collation and Non-Hidden Options
-````````````````````````````````````
-
-With the exception of the :ref:`collation option
-<createIndexes-collation-option>`, if you create an index with one set
-of index options and then try to recreate the same index but with
-different index options, MongoDB will not change the options nor
-recreate the index.
+Non-Hidden Option
+`````````````````
 
 The :ref:`hidden <createIndexes-hidden-option>` option can be changed
 without dropping and recreating the index. See
 :ref:`createIndexes-hidden-option`.
 
-To change the other index options, drop the existing index with
-:method:`db.collection.dropIndex()` before running 
-:dbcommand:`createIndexes` with the new options.
+Changing Index Options
+``````````````````````
+
+Collation options on an existing index can be updated. To change other 
+index options, drop the existing index with 
+:method:`db.collection.dropIndex()` then run :dbcommand:`createIndexes`
+with the new options.
 
 .. _createIndexes-collation-option:
 

source/release-notes/5.0.txt

@@ -373,10 +373,19 @@ Indexes
 -------
 
 Partial Indexes Behavior Change
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 .. include:: /includes/fact-5.0-multiple-partial-index.rst
 
+Unique Sparse Index Behavior Change
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Starting in MongoDB 5.0, :ref:`unique sparse <sparse-unique-index>` 
+and :ref:`unique non-sparse <unique-index>` indexes with the same 
+:ref:`key pattern<key_patterns>` can exist on a single collection.
+
+See :ref:`unique sparse index creation <sparse-and-non-sparse_example>`
+
 Cannot Drop ``Ready`` Indexes During In-Progress Index Builds
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~