Add mode to overwrite table if already exists

docs/src/basic.md

@@ -25,6 +25,10 @@ tbl = db.create_table("my_table",
 Under the hood, LanceDB is converting the input data into an Apache Arrow table
 and persisting it to disk in [Lance format](github.com/eto-ai/lance).
 
+If the table already exists, LanceDB will raise an error by default.
+If you want to overwrite the table, you can pass in `mode="overwrite"`
+to the `create_table` method.
+
 You can also pass in a pandas DataFrame directly:
 ```python
 import pandas as pd

python/lancedb/db.py

@@ -55,7 +55,11 @@ class LanceDBConnection:
         return self.open_table(name)
 
     def create_table(
-        self, name: str, data: DATA = None, schema: pa.Schema = None
+        self,
+        name: str,
+        data: DATA = None,
+        schema: pa.Schema = None,
+        mode: str = "create",
     ) -> LanceTable:
         """Create a table in the database.
 
@@ -67,6 +71,10 @@ class LanceDBConnection:
             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
         ----
@@ -78,7 +86,7 @@ class LanceDBConnection:
         A LanceTable object representing the table.
         """
         if data is not None:
-            tbl = LanceTable.create(self, name, data, schema)
+            tbl = LanceTable.create(self, name, data, schema, mode=mode)
         else:
             tbl = LanceTable(self, name)
         return tbl

python/lancedb/table.py

@@ -156,10 +156,10 @@ class LanceTable:
         return LanceQueryBuilder(self, query)
 
     @classmethod
-    def create(cls, db, name, data, schema=None):
+    def create(cls, db, name, data, schema=None, mode="create"):
         tbl = LanceTable(db, name)
         data = _sanitize_data(data, schema)
-        lance.write_dataset(data, tbl._dataset_uri, mode="create")
+        lance.write_dataset(data, tbl._dataset_uri, mode=mode)
         return tbl
 
 

python/tests/test_db.py

@@ -13,6 +13,7 @@
 
 import lancedb
 import pandas as pd
+import pytest
 
 
 def test_basic(tmp_path):
@@ -49,7 +50,13 @@ def test_ingest_pd(tmp_path):
     assert db.uri == str(tmp_path)
     assert db.table_names() == []
 
-    data = pd.DataFrame({"vector": [[3.1, 4.1], [5.9, 26.5]], "item": ["foo", "bar"], "price": [10.0, 20.0]})
+    data = pd.DataFrame(
+        {
+            "vector": [[3.1, 4.1], [5.9, 26.5]],
+            "item": ["foo", "bar"],
+            "price": [10.0, 20.0],
+        }
+    )
     table = db.create_table("test", data=data)
     rs = table.search([100, 100]).limit(1).to_df()
     assert len(rs) == 1
@@ -64,3 +71,28 @@ def test_ingest_pd(tmp_path):
     assert len(db) == 1
 
     assert db.open_table("test").name == db["test"].name
+
+
+def test_create_mode(tmp_path):
+    db = lancedb.connect(tmp_path)
+    data = pd.DataFrame(
+        {
+            "vector": [[3.1, 4.1], [5.9, 26.5]],
+            "item": ["foo", "bar"],
+            "price": [10.0, 20.0],
+        }
+    )
+    db.create_table("test", data=data)
+
+    with pytest.raises(Exception):
+        db.create_table("test", data=data)
+
+    new_data = pd.DataFrame(
+        {
+            "vector": [[3.1, 4.1], [5.9, 26.5]],
+            "item": ["fizz", "buzz"],
+            "price": [10.0, 20.0],
+        }
+    )
+    tbl = db.create_table("test", data=new_data, mode="overwrite")
+    assert tbl.to_pandas().item.tolist() == ["fizz", "buzz"]