Appengine Search API vs Datastore

Question

I am trying to decide whether I should use App-engine Search API or Datastore for an App-engine Connected Android Project. The only distinction that the google documentation makes is

... an index search can find no more than 10,000 matching documents. The App Engine Datastore may be more appropriate for applications that need to retrieve very large result sets.

Given that I am already very familiar with the Datastore: Will someone please help me, assuming I don't need 10,000 results?

• Are there any advantages to using the Search API versus using Datastore for my queries (per the quote above, it seems sensible to use one or the other)? In my case the end user must be able to search, update existing entries, and create new entities. For example if my app is a bookstore, the user must be able to add new books, add reviews to existing books, search for a specific book.
• My data structure is such that the content will be supplied by the end user. Document vs Datastore entity: which is cheaper to update? $$, etc.
• Can they supplement each other: Datastore and Search API? What's the advantage? Why would someone consider pairing the two? What's the catch/cost?

Answer 1

The key difference is that with the Datastore you cannot search inside entities. If you have a book called "War and peace", you cannot find it if a user types "war peace" in a search box. The same with reviews, etc. Therefore, it's not really an option for you.