CODEWITHSUNDEEP
python-2.7google-app-enginegoogle-cloud-datastore
Sahibzada
Sahibzada

Reputation: 153

How to jump to specific page using Query Cursor?

I am developing my website in python(webapp2) and google data store in back end. I have added query cursor for pagination and it's working good but it has only next and previous functions for pagination, the question is that how i will jump to specific page like i am on page 1 and i want to jump to page 3, how i will manage it in Query Cursor?

i have also visited below links but didn't find any solution https://www.the-swamp.info/blog/pagination-google-app-engine/

https://cloud.google.com/appengine/docs/standard/python/datastore/query-cursors

Upvotes: 2

Views: 1614

Answers (1)

Paolo Casciello
Paolo Casciello

Reputation: 8202

You can't. Datastore doesn't know the number of results found by your query.

You can however use some tricks to simulate a full pagination. For example one technique is to generate a certain number of cursors in a loop and generating the "last page" one.

Like in the following pseudo-code:

(results, next_curs, more) = model.query....fetch_page(...)

for p in xrange(5):
    # generate cursor for page number 'b' 
    # by using the next_cursor from previous page
    (results, next_curs, more) = model.....fetch_page(cursor=next_cursor,...)

As you don't access the results cursor the performance is somewhat acceptable (depending on your models complexity, query complexity and such). You can tweak it on your data.

Upvotes: 3

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