DML (UPDATE/DELETE)

README.md

@@ -137,6 +137,18 @@ Python |
 Go |
 node.js
 
+### Query - UPDATE and DELETE
+
+Show how these statements can be used to modify existing documents using
+secondary document attributes. Also show how a single document can be
+modified via the `USE KEYS` clause.
+
+C |
+[Python](python/n1ql-update-delete.py)
+| .NET |
+Go |
+node.js
+
 ### CAS Handling - Using CAS for concurrent mutations
 This example will demonstrate concurrent mutations with and without using the
 CAS value. Without using the CAS value, some modifications may end up getting

python/n1ql-update-delete.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python
+from couchbase.bucket import Bucket
+from couchbase.n1ql import N1QLQuery
+
+cb = Bucket('couchbase://localhost/default')
+
+# Create a set of 'product' documents
+docs = {
+    'bundt_cake_pan1': {
+        'type': 'product',
+        'name': 'Bundt Cake Pan',
+        'price': 7.35,
+        'categories': ['kitchen', 'home']
+    },
+    'led_4d_900in_tv1': {
+        'type': 'product',
+        'name': '4D 900" LED TV',
+        'price': 1250000.99,
+        'categories': ['technology', 'electronics']
+    },
+    'light_bulb_40w_led': {
+        'type': 'product',
+        'name': '40-Watt LED Bulb',
+        'price': 4.40,
+        'categories': ['electronics', 'home']
+    },
+    'red_puff_parka3': {
+        'type': 'product',
+        'name': 'Parka (red)',
+        'price': 54.99,
+        'categories': ['clothing']
+    },
+    'utilikilt1_speaker': {
+        'type': 'product',
+        'name': 'Utilikilt with Bluetooth Speaker in Rear',
+        'price': 124.95,
+        'categories': ['clothing', 'electronics', 'technology']
+    }
+}
+
+# Delete any prior products so we start with a clean dataset
+meta = cb.n1ql_query(
+    N1QLQuery('DELETE from default WHERE type=$1', 'product')
+).execute().meta
+print 'Deleted {0} items!'.format(meta['metrics'].get('mutationCount', 0))
+
+# Everything's 25% off!
+cb.upsert_multi(docs)
+query = N1QLQuery(
+    'UPDATE default '
+    'SET sale_price=ROUND(price-(price * 0.25), 2) '
+    'WHERE type=$1'
+    'RETURNING name, price, sale_price',
+    'product'
+)
+for row in cb.n1ql_query(query):
+    print '{0} WAS: {1:2}. NOW ONLY {2:2}'.format(
+        row['name'], row['price'], row['sale_price'])
+
+# Show how we can update a single document by its ID
+query = N1QLQuery(
+    'UPDATE default USE KEYS $keys SET description=$desc',
+    keys=['utilikilt1_speaker'],
+    desc='Use this handy utilikilt as a fashion accessory or in the garage, and lets '
+)
+cb.n1ql_query(query).execute()
+# Show the new value
+print cb.get('utilikilt1_speaker').value['description']