Files
lancedb/python/lancedb/db.py
2023-05-05 11:27:09 -07:00

115 lines
3.3 KiB
Python

# Copyright 2023 LanceDB Developers
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import annotations
from pathlib import Path
import pyarrow as pa
from .common import DATA, URI
from .table import LanceTable
from .util import get_uri_scheme
class LanceDBConnection:
"""
A connection to a LanceDB database.
"""
def __init__(self, uri: URI):
is_local = isinstance(uri, Path) or get_uri_scheme(uri) == "file"
if is_local:
if isinstance(uri, str):
uri = Path(uri)
uri = uri.expanduser().absolute()
Path(uri).mkdir(parents=True, exist_ok=True)
self._uri = str(uri)
@property
def uri(self) -> str:
return self._uri
def table_names(self) -> list[str]:
"""Get the names of all tables in the database.
Returns
-------
A list of table names.
"""
if get_uri_scheme(self.uri) == "file":
return [p.stem for p in Path(self.uri).glob("*.lance")]
raise NotImplementedError(
"List table_names is only supported for local filesystem for now"
)
def __len__(self) -> int:
return len(self.table_names())
def __contains__(self, name: str) -> bool:
return name in self.table_names()
def __getitem__(self, name: str) -> LanceTable:
return self.open_table(name)
def create_table(
self,
name: str,
data: DATA = None,
schema: pa.Schema = None,
mode: str = "create",
) -> LanceTable:
"""Create a table in the database.
Parameters
----------
name: str
The name of the table.
data: list, tuple, dict, pd.DataFrame; optional
The data to insert into the table.
schema: pyarrow.Schema; optional
The schema of the table.
mode: str; default "create"
The mode to use when creating the table.
By default, if the table already exists, an exception is raised.
If you want to overwrite the table, use mode="overwrite".
Note
----
The vector index won't be created by default.
To create the index, call the `create_index` method on the table.
Returns
-------
A LanceTable object representing the table.
"""
if data is not None:
tbl = LanceTable.create(self, name, data, schema, mode=mode)
else:
tbl = LanceTable(self, name)
return tbl
def open_table(self, name: str) -> LanceTable:
"""Open a table in the database.
Parameters
----------
name: str
The name of the table.
Returns
-------
A LanceTable object representing the table.
"""
return LanceTable(self, name)