yuna-db 0.1.1

Yuna DB: dict-like semantics for LMDB

Yuna DB: dict-like semantics for LMDB

Yuna is a key/value store that's built upon LMDB (the Symas Lightning Memory-mapped Database). LMDB really is lightning-fast, but as a C library only allows you to lookup a byte string value, using either an integer key or a byte string key.

Yuna provides semantics similar to a dict. You can specify a serialization format, and optionally a compression format to use, and Yuna will serialize values and write them to the database as byte strings. It will automatically recover the value from the bytes string.

For example, if x is any Python value that can be serialized by the chosen serialization format in table foo, this would work:

db.tables.foo.put(key, x)

After that .put() you can call .get():

x = db.tables.foo.get(key)

Example

from yuna import Yuna, SERIALIZE_JSON, SERIALIZE_STR

db = Yuna("/tmp/test.ydb", create=True)
db.new_table("names", serialize=SERIALIZE_JSON)

key = "feynman"
value = dict(first_name="Richard", last_name="Feynman")
db.tables.names.put(key, value)

temp = db.tables.names.get(key)
assert temp == value

db.new_table("abbrevs", serialize=SERIALIZE_STR)
key = "l8r"
value = "see you later"

db.tables.abbrevs.put(key, value)
temp = db.tables.abbrevs.get(key)
assert temp == value

db.close()

Planned new features to come:

• Implement a context manager on the Yuna class
• Support integer keys with a .insert() method providing autoincrement
• Finish the Zstandard compression support
• Add iterators to quickly find keys within a specified range
• Add a REPL (Python with the yuna module already loaded and the DB open)