747b0392__5_1___Postgres_OnLine_Journal__Microsoft_SQL_Server_2008
[Feature] Transactional DDL - ability to rollback CREATE, ALTER etc statements [MySQL 5.1] No [PostgreSQL 8.4] Yes - see this comparative analysis [Microsoft SQL Server 2008] 
Yes (I couldn't find any documentation on this, but I tested it and it correctly rolls back). There is a caveat that can't roll back DDL within a DDL trigger.
Cross Compare of PostgreSQL 8.4, SQL Server 2008, MySQL 5.1 - Postgres OnLine Journal
Microsoft SQL Server 2008