DDL can be generated from your mapping files by a Hibernate utility. The generated schema includes referential integrity constraints, primary and foreign keys, for entity and collection tables. Tables and sequences are also created for mapped identifier generators.
So always we need to specify a SQL Dialect via the hibernate.dialect property when using this tool, as DDL is highly vendor-specific. For this First, we need to must customize your mapping files to improve the generated schema. The next section covers schema customization.