docs: show how to delete rows in user guide (#309)

Closes #265
This commit is contained in:
Will Jones
2023-07-18 08:19:48 -07:00
committed by GitHub
parent 23f5dddc7c
commit 3537afb2c3
18 changed files with 549 additions and 110 deletions

View File

@@ -89,3 +89,6 @@ class RemoteTable(Table):
def _execute_query(self, query: Query) -> pa.Table:
result = self._conn._client.query(self._name, query)
return self._conn._loop.run_until_complete(result).to_arrow()
def delete(self, predicate: str):
raise NotImplementedError

View File

@@ -202,6 +202,51 @@ class Table(ABC):
def _execute_query(self, query: Query) -> pa.Table:
pass
@abstractmethod
def delete(self, where: str):
"""Delete rows from the table.
This can be used to delete a single row, many rows, all rows, or
sometimes no rows (if your predicate matches nothing).
Parameters
----------
where: str
The SQL where clause to use when deleting rows. For example, 'x = 2'
or 'x IN (1, 2, 3)'. The filter must not be empty, or it will error.
Examples
--------
>>> import lancedb
>>> import pandas as pd
>>> data = pd.DataFrame({"x": [1, 2, 3], "vector": [[1, 2], [3, 4], [5, 6]]})
>>> db = lancedb.connect("./.lancedb")
>>> table = db.create_table("my_table", data)
>>> table.to_pandas()
x vector
0 1 [1.0, 2.0]
1 2 [3.0, 4.0]
2 3 [5.0, 6.0]
>>> table.delete("x = 2")
>>> table.to_pandas()
x vector
0 1 [1.0, 2.0]
1 3 [5.0, 6.0]
If you have a list of values to delete, you can combine them into a
stringified list and use the `IN` operator:
>>> to_remove = [1, 5]
>>> to_remove = ", ".join([str(v) for v in to_remove])
>>> to_remove
'1, 5'
>>> table.delete(f"x IN ({to_remove})")
>>> table.to_pandas()
x vector
0 3 [5.0, 6.0]
"""
raise NotImplementedError
class LanceTable(Table):
"""
@@ -496,31 +541,6 @@ class LanceTable(Table):
return tbl
def delete(self, where: str):
"""Delete rows from the table.
Parameters
----------
where: str
The SQL where clause to use when deleting rows.
Examples
--------
>>> import lancedb
>>> import pandas as pd
>>> data = pd.DataFrame({"x": [1, 2, 3], "vector": [[1, 2], [3, 4], [5, 6]]})
>>> db = lancedb.connect("./.lancedb")
>>> table = db.create_table("my_table", data)
>>> table.to_pandas()
x vector
0 1 [1.0, 2.0]
1 2 [3.0, 4.0]
2 3 [5.0, 6.0]
>>> table.delete("x = 2")
>>> table.to_pandas()
x vector
0 1 [1.0, 2.0]
1 3 [5.0, 6.0]
"""
self._dataset.delete(where)
def _execute_query(self, query: Query) -> pa.Table: