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The page "IsoFormattedDateAsDocId" has been deleted by JoanTouzet: https://wiki.apache.org/couchdb/IsoFormattedDateAsDocId?action=diff&rev1=10&rev2=11 Comment: See http://docs.couchdb.org/en/stable/best-practices/index.html - = Using an ISO Formated Date as a Doc _id = - The ISO 8601 http://en.wikipedia.org/wiki/ISO_8601 standard 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: - {{{#!javascript - { - "sum_by_day": { - "map": "function(doc) {\n var dt = new Date(doc._id);\n emit([dt.getDate() doc.widget], 1);\n}", - "reduce": "function(keys, values, rereduce) {\n return sum(values)\n}" - } - } - }}} - . . . then simply use group_level to zoom in on whatever time you wish to use. - - {{{#!javascript - 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: - - {{{#!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); - } - }}} - If you have python views enabled, you can use the datetime module in the same way: - - {{{#!python - def fun(doc): - from datetime import datetime - dt = datetime.strptime(doc._id, "%Y-%m-%dT%H:%M:%S.%f") - yield [doc.host, dt.year, dt.month, dt.day, dt.hour, dt.minute], 1 - }}} - . . .example with reduce function as it appears in the design doc: - - {{{#!javascript - { - "doo_dad_finder": { - "map": "def fun(doc):\n from datetime import datetime\n if doc['errors']:\n dt = datetime.strptime(doc._id, '%Y-%m-%dT%H:%M:%S.%f')\n for doo_dad in doc['doo_dads']:\n yield [doo_dad, dt.year, dt.month, dt.hour], 1", - "reduce": "def fun(keys, values, rereduce):\n return sum(values)" - } - } - }}} - A nice example using a date within a document is found here: http://www.couchone.com/migrating-to-couchdb#three [dead link] [[http://web.archive.org/web/20110130042049/http://www.couchone.com/migrating-to-couchdb#three|Archive.org copy]] -
