rethinkDB pluck generated_key from insert python

Question

Essentially, I'm trying to get the generated key for a single record insert. Something like:

rethinkdb.table('test').insert(request.data).pluck('generated_keys')[0].run(connection)

and have it return something like:

{
    "id": "61fa30de-cfb1-4133-ae86-cf6e4f1a011e"
}

Answer 1

I just want to give some tips so that you can figure this out later. First, you can use typeOf to find the type of data.

r.table('dummy').insert({f: "foo"}).typeOf()
"OBJECT"

So you know if returns an object. Next, you go to RethinkDB document, try to find some similar function. A good guess is get_field http://rethinkdb.com/api/javascript/get_field/

And get_field can be called on object:

sequence.getField(attr) → sequence

singleSelection.getField(attr) → value

object.getField(attr) → value

Let's see what it returns it:

r.table('dummy').insert({f: "foo"}).getField('generated_keys').typeOf()
"ARRAY"

Let's find a command to return an element in array. You can go over the document again and will be noticed nth command to return a n-th element from an array. Therefore, we can do this now:

r.table('dummy').insert({f: "foo"}).getField('generated_keys').nth(0)
"c2b1bf69-a926-4c27-b1a6-011d47c700df"

Let's try to simplify it. Using getField is annyoing. To make it short, you can use bracket () to get a single field from object

r.table('dummy').insert({f: "foo"})('generated_keys').nth(0)
"77f4aca6-9219-494e-9998-23eb9abcd5e0"

But using nth also field annyoying a bit. Can we make it short. Luckily bracket can also be call on array.http://rethinkdb.com/api/javascript/bracket/

The () command also accepts integer arguments as array offsets, like the nth command.

Combine everything we have:

r.table('dummy').insert({f: "foo"})('generated_keys')(0)

This is all run direcly on Data Explorer but I think you can easily convert them into Python by looking at JavaScript and translate into Python.

Answer 2

In Python, If you want to return an array of all primary keys for the inserted documents, you can do the following:

 r.table('test').insert({ "hello": 'world' })['generated_keys'].run(conn)

If you want the query to return the primary key of the first inserted document as a string, you can do the following:

r.table('test').insert({ "hello": 'world' })['generated_keys'][0].run(conn)