Java Stored Procedures Developer's Guide
To help you build powerful database applications, stored procedures provide several advantages including better performance, higher productivity, ease of use, and increased scalability.
Stored procedures are compiled once and stored in executable form, so procedure calls are quick and efficient. Executable code is automatically cached and shared among users. This lowers memory requirements and invocation overhead.
By grouping SQL statements, a stored procedure allows them to be executed with a single call. This minimizes the use of slow networks, reduces network traffic, and improves round-trip response time. OLTP applications, in particular, benefit because result set processing eliminates network bottlenecks.
Additionally, stored procedures enable you to take advantage of the computing resources of the server. For example, you can move computation-bound procedures from client to server, where they will execute faster. Likewise, stored functions called from SQL statements enhance performance by executing application logic within the server.
By designing applications around a common set of stored procedures, you can avoid redundant coding and increase your productivity. Moreover, stored procedures let you extend the functionality of the RDBMS. For example, stored functions called from SQL statements enhance the power of SQL.
You can use the Java integrated development environment (IDE) of your choice to create stored procedures. Then, you can deploy them on any tier of the network architecture. Moreover, they can be called by standard Java interfaces such as JDBC, CORBA, and EJB and by programmatic interfaces and development tools such as SQLJ, the OCI, Pro*C/C++, and JDeveloper.
This broad access to stored procedures lets you share business logic across applications. For example, a stored procedure that implements a business rule can be called from various client-side applications, all of which can share that business rule. In addition, you can leverage the server's Java facilities while continuing to write applications for your favorite programmatic interface.
Stored procedures increase scalability by isolating application processing on the server. In addition, automatic dependency tracking for stored procedures aids the development of scalable applications.
The shared memory facilities of the Multi-Threaded Server (MTS) enable Oracle8i to support more than 10,000 concurrent users on a single node. For more scalability, you can use the Net8 Connection Manager to multiplex Net8 connections.
Once it is validated, a stored procedure can be used with confidence in any number of applications. If its definition changes, only the procedure is affected, not the applications that call it. This simplifies maintenance and enhancement. Also, maintaining a procedure on the server is easier than maintaining copies on various client machines.
Within the RDBMS, Java conforms fully to the Java Language Specification and furnishes all the advantages of a general-purpose, object-oriented programming language. Also, like PL/SQL, Java provides full access to Oracle data, so any procedure written in PL/SQL can be written in Java.
PL/SQL stored procedures complement Java stored procedures. Typically, SQL programmers who want procedural extensions favor PL/SQL, and Java programmers who want easy access to Oracle data favor Java.
The RDBMS allows a high degree of interoperability between Java and PL/SQL. Java applications can call PL/SQL stored procedures using an embedded JDBC driver. Conversely, PL/SQL applications can call Java stored procedures directly.
You can restrict access to Oracle data by allowing users to manipulate the data only through stored procedures that execute with their definer's privileges. For example, you can allow access to a procedure that updates a database table, but deny access to the table itself.
With Oracle Advanced Replication, stored procedures can be replicated (copied) from one Oracle8i database to another. This feature makes them ideal for implementing a central set of business rules. Once written, the stored procedures are replicated and distributed to work groups and branch offices throughout the company. In this way, policies can be revised on a central server rather than on individual servers.