Replace deprecated Engine.execute

Engine.execute was remvoed in SQLAlchemy 2.0.

Change-Id: I3a3e3263c54742ba793b293a2358f6e8202c21bb

tools/schema_generator.py

@@ -17,6 +17,7 @@
 import contextlib
 import re
 
+import sqlalchemy as sa
 import tabulate
 
 from taskflow.persistence.backends import impl_sqlalchemy
@@ -53,7 +54,8 @@ def main():
         with contextlib.closing(backend.get_connection()) as conn:
             conn.upgrade()
         # Now make a prettier version of that schema...
-        tables = backend.engine.execute(TABLE_QUERY)
+        with backend.engine.connect() as conn, conn.begin():
+            tables = conn.execute(sa.text(TABLE_QUERY))
             table_names = [r[0] for r in tables]
             for i, table_name in enumerate(table_names):
                 pretty_name = NAME_MAPPING.get(table_name, table_name)
@@ -61,7 +63,7 @@ def main():
                 # http://www.sqlite.org/faq.html#q24
                 table_name = table_name.replace("\"", "\"\"")
                 rows = []
-            for r in backend.engine.execute(SCHEMA_QUERY % table_name):
+                for r in conn.execute(sa.text(SCHEMA_QUERY % table_name)):
                     # Cut out the numbers from things like VARCHAR(12) since
                     # this is not very useful to show users who just want to
                     # see the basic schema...