Query language
FluidDB provides a simple query language that allows applications to search
for objects based on their tags’ values. The following kinds of queries are
possible:
- Equality & Inequality: To find objects based on the numeric value of
tags, e.g., tim/rating > 5, or exact textual values,
e.g., geo/name = "Llandefalle".
- Textual: To find objects based on text matching of their tag values,
e.g., sally/opinion matches fantastic. Text matching is done with
Lucene, meaning that Lucene
matching capabilities and style will be available .
- Presence: Use has to request objects that have a given tag. For
example, has sally/opinion.
- Set contents: A tag on an object can hold a set of strings. For
example, a tag called mary/product-reviews/keywords might be on an
object with a value of [ "cool", "kids", "adventure" ]. The
contains operator can be used to select objects with a matching
value. The query mary/product-reviews/keywords contains
"kids" would match the object in this example.
- Exclusion: You can exclude objects with the except keyword. For
example has nytimes.com/appeared except has james/seen. The
except operator performs a set difference.
- Logic: Query components can be combined with and and or. For
example, has sara/rating and tim/rating > 5.
- Grouping: Parentheses can be used to group query components. For
example, has sara/rating and (tim/rating > 5 or mike/rating > 7).
That’s it!
Query result limits
The main current limit is that queries may only return up to 1 million
objects. If a query generates more than this, an error status is returned.
If you need a higher limit, please email us.
Notes
