> On Sep 29, 2014, at 10:16 PM, peng liu <[email protected]> wrote:
>
> i have a user model. and has "pro" and "older",i want query "pro> 75 and
> 5<older<10" ,how to do that on couchbase ios? i have try set startKey and
> endKey but not work.
Unfortunately you can't do that query with just an index lookup. You've got the
index keys set up correctly, but the way the rows are ordered doesn't allow
more than one of the keys to be range-checked. The best you can do is query
over the desired range of the primary key; you'll have to filter on the
secondary key yourself.
So in your example, you would set
query.startKey = @{@75, @{}}
and no endKey. You'd then iterate the results and manually test the secondary
key:
for (CBLQueryRow* row in [query run: &error]) {
int older = [row.key2 intValue];
if (older > 5 && older < 10) {
… use the row …
}
}
This is actually a perfect use case for the new postFilter attribute that's
available on the feature/query branch. On that branch you can modify the query
like this:
query.postFilter = [NSPredicate predicateWithFormat: @"key2 > 5 and
key2 < 10"];
and it will then produce only the results you want.
(And in fact this is exactly what a SQL query would do — the query planner
would realize the index lookup could only filter on the primary key, so it
would then internally post-filter the results to check the secondary key. The
CBLQueryPlanner class that's also available on the feature/query branch will do
the same thing if you give it a query like this, including designing the view
for you!)
—Jens
PS: The cool new query tools on the feature/query branch are just one of the
upcoming features I'll be talking about in my "The Future Of Couchbase Lite"
talk at the Couchbase Connect conference next Tuesday! Be there!
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