From 68ff95142e6b77f81b0431abadd7c85e1e2fdb76 Mon Sep 17 00:00:00 2001
From: Martin Burchell <mb2353@cam.ac.uk>
Date: Mon, 17 Mar 2025 14:10:51 +0000
Subject: [PATCH 1/2] Always commit when executing DDL

This fixes a problem seen when preprocessing SystmOne data on the CPFT server.
If a 'crate_pk' column was added to a table and an index created on this column,
SQL Server would report that this column didn't exist
---
 cardinal_pythonlib/sqlalchemy/schema.py | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/cardinal_pythonlib/sqlalchemy/schema.py b/cardinal_pythonlib/sqlalchemy/schema.py
index f584119..6d0201e 100644
--- a/cardinal_pythonlib/sqlalchemy/schema.py
+++ b/cardinal_pythonlib/sqlalchemy/schema.py
@@ -417,8 +417,18 @@ def execute_ddl(
     if sql:
         ddl = DDL(sql)
     with engine.connect() as connection:
-        # DDL doesn't need a COMMIT.
         connection.execute(ddl)
+        # DDL may need a commit for some dialects:
+        #
+        # Generic (but generic may not be useful)
+        #     https://stackoverflow.com/questions/730621/do-ddl-statements-always-give-you-an-implicit-commit-or-can-you-get-an-implicit
+        # Oracle - autocommitted?
+        #     https://docs.oracle.com/cd/A97335_02/apps.102/a83723/keyprog6.htm
+        # but not Postgres?
+        #     https://dba.stackexchange.com/questions/340916/why-must-i-commit-after-the-alter-table-ddl-to-make-changes-visible
+        # and in SQL Server they are "batched" so not entirely autocommitted
+        #     https://www.mssqltips.com/sqlservertip/4591/ddl-commands-in-transactions-in-sql-server-versus-oracle/
+        connection.commit()
 
 
 # =============================================================================

From 9bbb52b68401fe5324c52a8b4a10a61df7ed053a Mon Sep 17 00:00:00 2001
From: Martin Burchell <mb2353@cam.ac.uk>
Date: Mon, 17 Mar 2025 15:10:53 +0000
Subject: [PATCH 2/2] Update changelog

---
 docs/source/changelog.rst | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/docs/source/changelog.rst b/docs/source/changelog.rst
index dd95a46..65ad7e3 100644
--- a/docs/source/changelog.rst
+++ b/docs/source/changelog.rst
@@ -880,3 +880,8 @@ Quick links:
 
 - Allow ``db_url`` parameter to
   ``cardinal_pythonlib.sqlalchemy.alembic_func.create_database_migration_numbered_style``.
+
+**2.0.4**
+
+- Fix :func:`cardinal_pythonlib.sqlalchemy.schema.execute_ddl` so that it always
+  commits. Not all dialects commit automatically.