feat: implement Approximate Nearest Neighbor support for DDL (CREATE TABLE, CREATE VECTOR INDEX)

README.rst

@@ -253,3 +253,9 @@ Disclaimer
 
 This is not an officially supported Google product.
 
+
+Limitations
+-----------
+
+* Approximate Nearest Neighbors (ANN) strategies are only supported for the GoogleSQL dialect
+* ANN's `ALTER VECTOR INDEX` is not yet supported by [Google Cloud Spanner](https://cloud.google.com/spanner/docs/find-approximate-nearest-neighbors#limitations)

noxfile.py

@@ -19,7 +19,6 @@
 import os
 import pathlib
 import shutil
-from pathlib import Path
 
 import nox
 
@@ -33,6 +32,7 @@
     "docfx",
     "docs",
     "format",
+    "integration",
     "lint",
     "unit",
 ]

requirements.txt

@@ -1,4 +1,4 @@
-google-cloud-spanner==3.49.1
-langchain-core==0.3.9
+google-cloud-spanner==3.51.0
+langchain-core==0.3.15
 langchain-community==0.3.1
 pydantic==2.9.1

src/langchain_google_spanner/graph_qa.py

@@ -288,6 +288,7 @@ def _call(
         inputs: Dict[str, Any],
         run_manager: Optional[CallbackManagerForChainRun] = None,
     ) -> Dict[str, str]:
+
         intermediate_steps: List = []
 
         """Generate gql statement, uses it to look up in db and answer question."""

src/langchain_google_spanner/graph_retriever.py

@@ -225,7 +225,7 @@ def __clean_element(self, element: dict[str, Any], embedding_column: str) -> Non
             del element["properties"][embedding_column]
 
     def __get_distance_function(
-        self, distance_strategy=DistanceStrategy.EUCLIDEIAN
+        self, distance_strategy=DistanceStrategy.EUCLIDEAN
     ) -> str:
         """Gets the vector distance function."""
         if distance_strategy == DistanceStrategy.COSINE: