Controlling reverse engineering

Controlling reverse engineering

When using the the ant task will read the database metadata and from that perform a reverse engineering of the database schema into a normal Hibernate Configuration. It is from this object e.g. >hbm2java<>

To govern this process Hibernate uses a reverse engineering strategy. A reverse engineering strategy is mainly called to provide more java like names for tables, column and foreignkeys into classes, properties and associations. It also used to provide mappings from SQL types to Hibernate types. The strategy can be customized by the user. The user can even provide its own custom reverse engineering strategy if the provided strategy is not enough, or simply just provide a small part of the strategy and delegate the rest to the default strategy.

5.1. Default reverse engineering strategy

The default strategy uses some rules for mapping JDBC artifact names to java artifact names. It also provide basic typemappings from JDBC types to Hibernate types. It is the default strategy that uses the packagename attribute to convert a table name to a fully qualified classname.

5.2. hibernate.reveng.xml file

To have fine control over the process a hibernate.reveng.xml file can be provided. In this file you can specify type mappings and table filtering. This file can be created by hand (its just basic XML) or you can use the Hibernate plugins which have a specialized editor.

Note: many databases is case-sensitive with their names and thus if you cannot make some table match and you are sure it is not excluded by a then check if the case matches; most databases stores table names in uppercase.

The following is an example of a reveng.xml. Following the example is more details about the format.