Conclusion

In this chapter we looked at how to use MySQL stored programs from within Java programs. Java programs access relational databases through the JDBC interfaces supported by the MySQL Connector/J driver.

We first reviewed the fundamentals of using JDBC to process basic SQLqueries, updates, inserts, deletes, DDL, and utility statements. We showed how to use the PreparedStatement interface to execute SQL statements that are repeatedly executed, possibly with variable query parameters or DML inputs. Finally, we looked at JDBC structures for implementing transaction and error handling.

JDBC fully supports stored programs through the CallableStatement interface. Callable statements support multiple result sets, and they support IN, OUT, and INOUT parameters. The ResultSetMetaData interface can be used to determine the structure of result sets returned by stored programs if this is not known in advance.

Stored programs are suitable for use in J2EE applications, and stored procedures can be invoked from within J2EE application servers such as JBoss, WebLogic, and WebSphere. We can use stored programs in J2EE applications wherever we might embed standard SQL callsfrom servlets, session EJBs, or Bean Managed Persistence (BMP) EJBs. However, stored programs cannot easily be leveraged from within Container Managed Persistence (CMP) EJBs.

We can use stored procedures in ORM frameworks such as Hibernate, although doing so involves more work than letting Hibernate generate its own native SQL. The Spring framework also provides full support for MySQL stored procedures.

As with other application development environments, the use of stored programs from within Java code offers a number of advantages, including encapsulation of complex transaction logic, abstraction of the underlying schema, and potential performance improvements from reduction in network round trips.