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diff --git a/heat/db/migrations/env.py b/heat/db/migrations/env.py
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+++ b/heat/db/migrations/env.py
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+# 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 logging.config import fileConfig
+
+from alembic import context
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from heat.db import models
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+if config.attributes.get('configure_logger', True):
+    fileConfig(config.config_file_name)
+
+# this is the MetaData object for the various models in the database
+target_metadata = models.BASE.metadata
+
+
+def run_migrations_offline() -> None:
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL and not an Engine, though an
+    Engine is acceptable here as well.  By skipping the Engine creation we
+    don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online() -> None:
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine and associate a connection
+    with the context.
+
+    This is modified from the default based on the below, since we want to
+    share an engine when unit testing so in-memory database testing actually
+    works.
+
+    https://alembic.sqlalchemy.org/en/latest/cookbook.html#connection-sharing
+    """
+    connectable = config.attributes.get('connection', None)
+
+    if connectable is None:
+        # only create Engine if we don't have a Connection from the outside
+        connectable = engine_from_config(
+            config.get_section(config.config_ini_section, {}),
+            prefix="sqlalchemy.",
+            poolclass=pool.NullPool,
+        )
+
+    # when connectable is already a Connection object, calling connect() gives
+    # us a *branched connection*
+
+    with connectable.connect() as connection:
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata,
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()