使用Google App Engine实现“Start with with”和“Ends with”查询

Question

Am wondering if anyone can provide some guidance on how I might implement a starts with or ends with query against a Datastore model using Python?

In pseudo code, it would work something like...

Query for all entities A where property P starts with X

or

Query for all entities B where property P ends with X

Thanks, Matt

Answer 1

You can do a 'starts with' query by using inequality filters:

MyModel.all().filter('prop >=', prefix).filter('prop <', prefix + u'\ufffd')

Doing an 'ends with' query would require storing the reverse of the string, then applying the same tactic as above.

Answer 2

Seems you can't do it for the general case, but can do it for prefix searches (starts with):

Wildcard search on Appengine in python