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Gord Thompson
dc91c7db7f
"Implicit autocommit", which is the COMMIT that occurs when a DML or DDL statement is emitted on a connection, is deprecated and won't be part of SQLAlchemy 2.0. A 2.0-style warning is emitted when autocommit takes effect, so that the calling code may be adjusted to use an explicit transaction. As part of this change, DDL methods such as :meth:`_schema.MetaData.create_all` when used against a :class:`_engine.Engine` or :class:`_engine.Connection` will run the operation in a BEGIN block if one is not started already. The MySQL and MariaDB dialects now query from the information_schema.tables system view in order to determine if a particular table exists or not. Previously, the "DESCRIBE" command was used with an exception catch to detect non-existent, which would have the undesirable effect of emitting a ROLLBACK on the connection. There appeared to be legacy encoding issues which prevented the use of "SHOW TABLES", for this, but as MySQL support is now at 5.0.2 or above due to 🎫`4189`, the information_schema tables are now available in all cases. Fixes: #4846 Change-Id: I733a7e0e17477a63607fb9931c87c393bbd7ac57