Work with nested objects using couchdb-python

Question

Disclaimer: Both Python and CouchDB are new for me. So far my "programming" has mostly consisted of Bash scripts.

I'm trying to create a small script that updates objects in a CouchDB database. The objects however aren't created by my script but by an App called Tap Forms that uses CouchDB for sync. Basically I'm trying to automatically update the content of the app. That also means I can't really influence the structure or names of the objects in CouchDB.

The Database is mostly filled with objects of this structure:

{
  "_id": "rec-3b17...",
  "_rev": "21-cdf6...",
  "values": {
    "fld-c3d4...": 4,
    "fld-1def...": 1000000000000,
    "fld-bb44...": 760000000000,
    "fld-a44f...": "admin,name",
    "fld-5fc0...": "SSD",
    "fld-642c...": true,
  },
  "deviceName": "MacBook Air",
  "dateModified": "2019-02-08T14:47:06.051Z",
  "dateCreated": "2019-02-08T11:33:00.018Z",
  "type": "frm-7ff3...",
  "dbID": "db-1435...",
  "form": "frm-7ff3..."
}

I shortened the numbers a bit and removed some entries to increase readability.

Now the actual values I'm trying to update are within the "values" : {...} array (or object, or list, guess I don't have much experience with JSON either). As I know some of these values, I managed to create view that finds the _id of an object on the server. I then use the python-couchdb module as described in documentation:

for item in db.view('CustomViews/test2', key="GENERIC"):
    doc = db[item.id]

This gives me the object. However I want to update one of the values within the values array, lets say fld-c3d4.... But how? Using doc['values'] = 'new_value' updates the whole array. I tried other (seemingly logical) ways along the lines of doc['values['fld-c3d4']'] = 'new_value' but couldn't wrap my head around it. I couldn't find an example in any documentation.

score 1 · Accepted Answer · answered Feb 09 '19 at 19:45

So here's a example how to update the fld-c3d4.

You have your document that represent a dictionary with nested dictionary.

If you want to get the values, you will do something like this:

values = doc['values']

Now the variable values points to the values in your document.

From there, you can access a sub value:

values['fld-c3d4'] = 'new value'

If you want to directly update the value from the doc, you just have to chain those operations:

doc['values']['fld-c3d4'] = 'new value'

I forgot to to thank you, sorry! But yeah, that did it. – lucaschultz Apr 23 '19 at 08:48 — lucaschultz, Apr 23 '19 at 08:48

Work with nested objects using couchdb-python

1 Answers1