PrefixDB was going to be a toy database that specialized in range scans of key-value pairs. The database was never completed. It does have a functional parser and lexer for the query language though.
There is a command-line tool that will read from stdin and write out the tokens under tools/lexer.
CREATE KEYSPACE acme.example.dynamite
DROP KEYSPACE acme
SELECT FROM users WHERE username = "bugs.bunny"
SELECT FROM users WHERE username = "bugs.bunny" OR "daffy.duck" AND timestamp BETWEEN "2015-01-01" AND "2016-01-01" AND topic = "hunting"
DELETE FROM users WHERE username = "bugs.bunny"
DELETE FROM users WHERE username = "bugs.bunny" OR "daffy.duck" AND timestamp BETWEEN "2015-01-01" AND "2016-01-01" AND topic = "hunting"
UPSERT "{...}" INTO users WHERE username = "bugs.bunny"`
UPSERT "{...}" INTO users.convo.timestamp WHERE username = "bugs.bunny" AND convo_id = "5" AND timestamp = "2015-01-01T00:00:00.001Z"
The parser is quite fast. Most queries are in the several microsecond range for parsing.
pkg: github.com/eliquious/prefixdb/parser
BenchmarkBadStatement-12 1000000 1115 ns/op
BenchmarkNestedCreateStatement-12 500000 3683 ns/op
BenchmarkCreateStatement-12 500000 2518 ns/op
BenchmarkDropStatement-12 1000000 2373 ns/op
BenchmarkSelectStatement-12 300000 4247 ns/op
BenchmarkComplexSelectStatement-12 200000 10344 ns/op
BenchmarkDeleteStatement-12 300000 4236 ns/op
BenchmarkComplexDeleteStatement-12 200000 10335 ns/op
BenchmarkUpsertStatement-12 300000 4737 ns/op
BenchmarkComplexUpsertStatement-12 200000 9772 ns/op
BenchmarkLargeUpsertStatement-12 100000 19269 ns/op
PASS
ok github.com/eliquious/prefixdb/parser 20.503s