[couchdb-documentation] branch master updated: Migration of MoinMoin ISO date content

[wohali]

This is an automated email from the ASF dual-hosted git repository.

wohali pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/couchdb-documentation.git


The following commit(s) were added to refs/heads/master by this push:
     new d116967  Migration of MoinMoin ISO date content
d116967 is described below

commit d116967e96e5200dd594eb4e8cd8cfbc0f8c1a8e
Author: Joan Touzet <jo...@atypical.net>
AuthorDate: Mon Dec 17 14:03:52 2018 -0500

    Migration of MoinMoin ISO date content
---
 src/best-practices/index.rst    |  1 +
 src/best-practices/iso-date.rst | 64 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/src/best-practices/index.rst b/src/best-practices/index.rst
index 01b4a05..f7e3ebd 100644
--- a/src/best-practices/index.rst
+++ b/src/best-practices/index.rst
@@ -26,6 +26,7 @@ system.
 
     documents
     forms
+    iso-date
     jsdevel
     views
     reverse-proxies
diff --git a/src/best-practices/iso-date.rst b/src/best-practices/iso-date.rst
new file mode 100644
index 0000000..c91c962
--- /dev/null
+++ b/src/best-practices/iso-date.rst
@@ -0,0 +1,64 @@
+.. Licensed under the Apache License, Version 2.0 (the "License"); you may not
+.. use this file except in compliance with the License. You may obtain a copy 
of
+.. the License at
+..
+..   http://www.apache.org/licenses/LICENSE-2.0
+..
+.. Unless required by applicable law or agreed to in writing, software
+.. distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+.. WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+.. License for the specific language governing permissions and limitations 
under
+.. the License.
+
+.. _best-practices/iso-date:
+
+============================================
+Using an ISO Formatted Date for Document IDs
+============================================
+
+The `ISO 8601 date standard <http://en.wikipedia.org/wiki/ISO_8601>`_ 
describes a useful
+scheme for representing a date string in a 
Year-Month-DayTHour:Minute:Second.microsecond
+format. For time-bound documents in a CouchDB database this can be a very 
handy way to
+create a unique identifier, since JavaScript can directly use it to create a 
Date object.
+Using this sample ``map`` function:
+
+.. code-block:: javascript
+
+    function(doc) {
+      var dt = new Date(doc._id);
+      emit([dt.getDate(), doc.widget], 1);
+    }
+
+simply use ``group_level`` to zoom in on whatever time you wish to use.
+
+.. code-block:: bash
+
+    curl -X GET 
"http://localhost:5984/transactions/_design/widget_count/_view/toss?group_level=1";
+
+    {"rows":[
+    {"key":[20],"value":10},
+    {"key":[21],"value":20}
+    ]}
+
+    curl -X GET 
"http://localhost:5984/transactions/_design/widget_count/_view/toss?group_level=2";
+
+    {"rows":[
+    {"key":[20,widget],"value":10},
+    {"key":[21,widget],"value":10},
+    {"key":[21,thing],"value":10}
+    ]}
+
+Another method is using ``parseint()`` and ``datetime.substr()`` to cut out 
useful values
+for a return key:
+
+.. code-block:: javascript
+
+    function (doc) {
+      var datetime = doc._id;
+      var year = parseInt(datetime.substr(0, 4));
+      var month = parseInt(datetime.substr(5, 2), 10);
+      var day = parseInt(datetime.substr(8, 2), 10);
+      var hour = parseInt(datetime.substr(11, 2), 10);
+      var minute = parseInt(datetime.substr(14, 2), 10);
+      emit([doc.widget, year, month, day, hour, minute], 1);
+    }