Yes, it is possible, but you need to be aware of limitations. I suggest understanding querying on List properties before starting: http://code.google.com/appengine/docs/java/datastore/queriesandindexes.html#Big_Entities_and_Exploding_Indexes
<http://code.google.com/appengine/docs/java/datastore/queriesandindexes.html#Big_Entities_and_Exploding_Indexes>Be very careful of exploding indexes. On Mon, Feb 22, 2010 at 3:41 PM, ka2 <[email protected]> wrote: > I was wondering if is there any way that > this would be possible to implement. I have a search criteria > that the user would fill out, most of the fields are multi-select, and > none is required, so I need to generate the query dynamically (at > least that would be a way to handle it in SQL, or store procs..) .Can > I use several contains() in a query? have any sample? can I use > executeWithMap to supply the lists for the several contains()? Can I > mix the lists with other kind of parameters in the map? Again a link > to a sample would be great. > > If not possible, the only other solution I can think off would be to > choose one of the fields in the criteria, hopefully the most > restrictive, get the results into memcache, and execute the rest of > the conditions sequentially, adding the results to the memcache by > using incrementAll(), and at the end check the counters for each > entity in the memcache, and get only the results where the hitCount is > equal to the number of queries. Would do the queries to get only IDs, > they say are faster, and at the end would get all the entities with > the resulting id set. Is there a better solution?, again preindexing > the records with all possible combinations doesn't seem to be a good > idea in this case. > > thanks > Karel > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine for Java" group. > To post to this group, send email to > [email protected]. > To unsubscribe from this group, send email to > [email protected]<google-appengine-java%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/google-appengine-java?hl=en. > > -- Ikai Lan Developer Programs Engineer, Google App Engine http://googleappengine.blogspot.com | http://twitter.com/app_engine -- You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en.
