googleapis · waltaskew · Sep 23, 2025
diff --git a/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py b/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py
@@ -719,6 +719,10 @@ def visit_create_index(
                     [self.preparer.quote(c.name) for c in storing_columns]
                 )
 
+            interleave_in = options.get("interleave_in")
+            if interleave_in is not None:
+                text += f", INTERLEAVE IN {self.preparer.quote(interleave_in)}"
+
             if options.get("null_filtered", False):
                 text = re.sub(
                     r"(^\s*CREATE\s+(?:UNIQUE\s+)?)INDEX",

diff --git a/samples/model.py b/samples/model.py
@@ -95,11 +95,22 @@ class Album(Base):
 
 class Track(Base):
     __tablename__ = "tracks"
-    # This interleaves the table `tracks` in its parent `albums`.
-    __table_args__ = {
-        "spanner_interleave_in": "albums",
-        "spanner_interleave_on_delete_cascade": True,
-    }
+    __table_args__ = (
+        # Use the spanner_interleave_in argument to add an INTERLEAVED IN clause to the index.
+        # You can read additional details at:
+        # https://cloud.google.com/spanner/docs/secondary-indexes#indexes_and_interleaving
+        Index(
+            "idx_tracks_id_title",
+            "id",
+            "title",
+            spanner_interleave_in="albums",
+        ),
+        # This interleaves the table `tracks` in its parent `albums`.
+        {
+            "spanner_interleave_in": "albums",
+            "spanner_interleave_on_delete_cascade": True,
+        },
+    )
     id: Mapped[str] = mapped_column(String(36), primary_key=True)
     track_number: Mapped[int] = mapped_column(Integer, primary_key=True)
     title: Mapped[str] = mapped_column(String(200), nullable=False)

diff --git a/test/mockserver_tests/interleaved_index.py b/test/mockserver_tests/interleaved_index.py
@@ -0,0 +1,74 @@
+# Copyright 2025 Google LLC All rights reserved.
+#
+# 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 sqlalchemy import ForeignKey, Index, String
+from sqlalchemy.orm import DeclarativeBase
+from sqlalchemy.orm import Mapped
+from sqlalchemy.orm import mapped_column
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+class Singer(Base):
+    __tablename__ = "singers"
+
+    singer_id: Mapped[str] = mapped_column(String(36), primary_key=True)
+    first_name: Mapped[str]
+    last_name: Mapped[str]
+
+
+class Album(Base):
+    __tablename__ = "albums"
+    __table_args__ = {
+        "spanner_interleave_in": "singers",
+        "spanner_interleave_on_delete_cascade": True,
+    }
+
+    singer_id: Mapped[str] = mapped_column(
+        ForeignKey("singers.singer_id"), primary_key=True
+    )
+    album_id: Mapped[str] = mapped_column(String(36), primary_key=True)
+    album_title: Mapped[str]
+
+
+class Track(Base):
+    __tablename__ = "tracks"
+    __table_args__ = (
+        Index(
+            "idx_name",
+            "singer_id",
+            "album_id",
+            "song_name",
+            spanner_interleave_in="albums",
+        ),
+        {
+            "spanner_interleave_in": "albums",
+            "spanner_interleave_on_delete_cascade": True,
+        },
+    )
+
+    singer_id: Mapped[str] = mapped_column(
+        ForeignKey("singers.singer_id"), primary_key=True
+    )
+    album_id: Mapped[str] = mapped_column(
+        ForeignKey("albums.album_id"), primary_key=True
+    )
+    track_id: Mapped[str] = mapped_column(String(36), primary_key=True)
+    song_name: Mapped[str]
+
+
+Album.__table__.add_is_dependent_on(Singer.__table__)
+Track.__table__.add_is_dependent_on(Album.__table__)
diff --git a/test/mockserver_tests/test_interleaved_index.py b/test/mockserver_tests/test_interleaved_index.py
@@ -0,0 +1,102 @@
+# Copyright 2025 Google LLC All rights reserved.
+#
+# 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 sqlalchemy import create_engine
+from sqlalchemy.testing import eq_, is_instance_of
+from google.cloud.spanner_v1 import (
+    FixedSizePool,
+    ResultSet,
+)
+from test.mockserver_tests.mock_server_test_base import (
+    MockServerTestBase,
+    add_result,
+)
+from google.cloud.spanner_admin_database_v1 import UpdateDatabaseDdlRequest
+
+
+class TestNullFilteredIndex(MockServerTestBase):
+    """Ensure we emit correct DDL for not null filtered indexes."""
+
+    def test_create_table(self):
+        from test.mockserver_tests.interleaved_index import Base
+
+        add_result(
+            """SELECT true
+FROM INFORMATION_SCHEMA.TABLES
+WHERE TABLE_SCHEMA="" AND TABLE_NAME="singers"
+LIMIT 1
+""",
+            ResultSet(),
+        )
+        add_result(
+            """SELECT true
+FROM INFORMATION_SCHEMA.TABLES
+WHERE TABLE_SCHEMA="" AND TABLE_NAME="albums"
+LIMIT 1
+""",
+            ResultSet(),
+        )
+        add_result(
+            """SELECT true
+FROM INFORMATION_SCHEMA.TABLES
+WHERE TABLE_SCHEMA="" AND TABLE_NAME="tracks"
+LIMIT 1
+""",
+            ResultSet(),
+        )
+        engine = create_engine(
+            "spanner:///projects/p/instances/i/databases/d",
+            connect_args={"client": self.client, "pool": FixedSizePool(size=10)},
+        )
+        Base.metadata.create_all(engine)
+        requests = self.database_admin_service.requests
+        eq_(1, len(requests))
+        is_instance_of(requests[0], UpdateDatabaseDdlRequest)
+        eq_(4, len(requests[0].statements))
+        eq_(
+            "CREATE TABLE singers (\n"
+            "\tsinger_id STRING(36) NOT NULL, \n"
+            "\tfirst_name STRING(MAX) NOT NULL, \n"
+            "\tlast_name STRING(MAX) NOT NULL\n"
+            ") PRIMARY KEY (singer_id)",
+            requests[0].statements[0],
+        )
+        eq_(
+            "CREATE TABLE albums (\n"
+            "\tsinger_id STRING(36) NOT NULL, \n"
+            "\talbum_id STRING(36) NOT NULL, \n"
+            "\talbum_title STRING(MAX) NOT NULL, \n"
+            "\tFOREIGN KEY(singer_id) REFERENCES singers (singer_id)\n"
+            ") PRIMARY KEY (singer_id, album_id),\n"
+            "INTERLEAVE IN PARENT singers ON DELETE CASCADE",
+            requests[0].statements[1],
+        )
+        eq_(
+            "CREATE TABLE tracks (\n"
+            "\tsinger_id STRING(36) NOT NULL, \n"
+            "\talbum_id STRING(36) NOT NULL, \n"
+            "\ttrack_id STRING(36) NOT NULL, \n"
+            "\tsong_name STRING(MAX) NOT NULL, \n"
+            "\tFOREIGN KEY(singer_id) REFERENCES singers (singer_id), \n"
+            "\tFOREIGN KEY(album_id) REFERENCES albums (album_id)\n"
+            ") PRIMARY KEY (singer_id, album_id, track_id),\n"
+            "INTERLEAVE IN PARENT albums ON DELETE CASCADE",
+            requests[0].statements[2],
+        )
+        eq_(
+            "CREATE INDEX idx_name ON tracks "
+            "(singer_id, album_id, song_name), "
+            "INTERLEAVE IN albums",
+            requests[0].statements[3],
+        )