Oracle does NOT have Boolean datatype

Oracle has no native BOOLEAN datatype. sqlalchemy.databases.oracle.OracleBoolean assumes incorrectly that it does (god knows why :S) Attached patch makes code work the same way as sqlalchemy.database.mssql.MSBoolean except 'SMALLINT' is used instead of 'BIT'.

Note: source of confusion might be that PL/SQL does have BOOLEAN type. You can't define table columns with it though.