> On Feb 2, 2015, at 5:36 PM, Kevin Lord <[email protected]> wrote:
>
> Is it possible to use any kind of regular expressions or wildcards in string
> keys when querying a view? I would really like to match on portions of a
> string aside from the beginning.
In general, you can do this by querying the entire view (i.e. not setting any
startKey or endKey) and then using a postFilter predicate to do the string
matching.
That may sound inefficient — and it is! — but that kind of search is inevitably
inefficient since it can't use an index to narrow down the keys. (A SQL query
would do exactly the same thing, behind the scenes.)
> eg. if I have a name property, with document that has the value "John Michael
> Smith", I would like to query using a key "*Smith" or "*Michael*" etc.
A much more efficient way to do a search like this would be to make your map
function emit each component of the name as a separate key. For example,
something like
emit(doc.firstName, nil);
if (doc.middleName) emit(doc.middleName, nil);
emit(doc.lastName, nil);
(You don't have to store the name broken into components like that; if it's in
a single string property, the map function can just split it by spaces and emit
each component.)
Then you can query for a name component like "Smith" or "Michael" by setting
that as the key, and find all instances of it.
—Jens
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