Oracle® Transparent Gateway for iWay Installation and User's Guide
10g Release 1 (10.1) for IBM z/OS (OS/390)
Part No. B13682-01
Oracle Enterprise Gateways simplify complex systems and remove obstacles to information. For detailed information on Oracle Heterogeneous Services, refer to Oracle Database Heterogeneous Connectivity Administrator's Guide.
This chapter contains the following topics:
The Oracle Database 10g server continues to improve its distributed database facilities that make the integration of enterprise data practical. Data can be accessed remotely using both SQL and PL/SQL procedure calls in a transparent manner, as if the data were local. Also, data can be stored in both Oracle Database 10g servers and non-Oracle servers.
Version 10 gateways are tightly integrated with the Oracle Database 10g server, enabling improved performance and enhanced functionality while still providing transparent integration of Oracle and non-Oracle data. For example, connection initialization information is available in the local Oracle Database server, reducing the number of round trips and the amount of data sent over the network. Running SQL is also faster, because statements issued by an application are parsed and translated once and can then be reused by multiple applications.
Version 10 gateways leverage the enhancements in the Oracle Database 10g server, and you can quickly extend those benefits to your non-Oracle data.
Oracle Transparent Gateway for iWay enables Oracle client applications to access the iWay Server through Structured Query Language (SQL). The gateway and Oracle Database 10g server together create the appearance that all data resides on a local Oracle Database 10g server, even though data might be widely distributed. If data is moved from an iWay Server database to an Oracle Database server, then no changes in client application design or function are needed. The gateway handles all differences in data types and SQL functions between the application and the database.
Oracle Transparent Gateway for iWay gives you the power to integrate your heterogeneous system into a single, seamless environment, enabling you to make full use of existing hardware and applications throughout your corporate-wide environment. You can eliminate the need to rewrite applications for each configuration and avoid the tedious, error-prone process of manual data transfer. Together with the Oracle tools, networking, and data server technology, Oracle Transparent Gateway for iWay sets the standard for seamless, enterprise-wide information access.
By using Oracle Transparent Gateway for iWay, you can achieve transparency at every level within your enterprise.
Users can access tables by name, without having to understand the physical location of the tables.
Operating system transparency
You can access data stored under multiple operating systems without being aware of the operating systems that hold the data.
Data storage transparency
Data can be accessed regardless of the database or file format.
Access method transparency
You can utilize a single dialect of SQL for any data store, eliminating the need to code for database-specific access methods or SQL implementations.
Your application can access all your data using Oracle SQL, which is rich in features. Advanced Oracle Database 10g server functions, such as outer joins, are available, even if the target data stores do not support them in a native environment. The manner in which the gateways are integrated with the Oracle Database 10g server ensures that the newest features of each database release are always available immediately to the gateway.
The Oracle Database 10g server can utilize its advanced query optimization techniques to ensure that SQL statements are run efficiently against any of your data. The data distribution and storage characteristics of local and remote data are considered equally.
The Oracle two-phase commit mechanism provides consistency across data stores by ensuring that a transaction that spans data stores is still treated as a single unit of work. Changes are not committed, nor permanently stored, in any data store unless the changes can be committed in all data stores that are affected.
The same Oracle stored procedures and database triggers can be used to access all of your data, ensuring uniform enforcement of your business rules across the enterprise.
The gateway integration with the Oracle Database 10g server extends to non-Oracle data the benefits of the Oracle Internet and Oracle Net, and the Oracle client/server and server/server connectivity software. These powerful features include:
Any Internet or intranet application that can access data from the Oracle Database server can also incorporate information from data stores that are accessible through the gateways. Web browsers can connect to the Oracle Database server using any application server product that supports Oracle software.
The Oracle Database server and Oracle Net can work together as a protocol converter, allowing applications to transparently access other data stores on platforms that do not support the client network protocol.
Non-Oracle data can be protected from unauthorized access or tampering during transmission to the client. This is done by using the hardware-independent and protocol-independent encryption and CHECKSUM services of Oracle Advanced Security (OAS).
Oracle Mobile Agents, an Oracle mobile technology, enables wireless communication to Oracle Database 10g servers or to any databases that are accessible through the gateways. This gives field personnel direct access to enterprise data from mobile laptop computers.
Inefficient duplication is not necessary with Oracle Transparent Gateway for iWay. This Oracle gateway uses the existing native dictionaries of iWay Server. Your applications access data by using the dictionaries that are designed specifically for each database, which means that no redundant dictionary ever needs to be created or maintained. The simple setup of the gateway does not require any additional mapping.
Before an application can access any information, the application must be told the structure of the data, such as the columns of a table and their lengths. Many products require administrators to manually define this information in a separate data dictionary that is stored in a hub. Applications then access information using the hub dictionary instead of using the native dictionaries of each database. This approach requires a great deal of manual configuration and maintenance on your part. As administrators, you must update the data dictionary in the hub whenever the structure of a remote table is changed.
Oracle Transparent Gateways ease your application development and maintenance by allowing you to access any data using a uniform set of SQL. Changes to the location, storage characteristics, or table structure do not require any changes to your applications. ANSI and ISO standard SQL are supported, along with powerful Oracle extensions.
The gateway enables you to exploit both Oracle and non-Oracle stored procedures, leveraging your investments in a distributed, multi-database environment. Oracle stored procedures can access and update multiple data stores easily, without any special coding for the heterogeneous data access.
Oracle stored procedures enable you to access and update iWay Server data using centralized business rules that are stored in the Oracle Database 10g server. Using Oracle stored procedures can increase your database performance by minimizing network traffic. Instead of sending individual SQL statements across the network, an application can send a single EXECUTE command to begin an entire PL/SQL routine.
Any application or tool that supports the Oracle Database 10g server can access more than 30 different data sources through the Oracle gateways. A wide variety of open system tools from Oracle Corporation and third-party vendors can be used, even if the data is stored in legacy, proprietary formats. Hundreds of tools are supported, including improvised query tools, web browsers, turnkey applications, and application development tools.
Use Oracle Developer to build applications that can manipulate data that is stored in your iWay Server database and Oracle Database server. This includes designing forms, producing graphic displays, and creating a wide range of objects.
Use Oracle Discoverer to analyze, manipulate, and copy data residing in your iWay Server database. This product gives you access to corporate data using a powerful data analysis tool.
Use SQL*Plus for moving data between the databases. This product gives you the ability to copy data between your department databases and your corporate Oracle Database servers.
The gateway is integrated into the Oracle Database 10g server technology, which provides global query optimization, transaction coordination for multi-site transactions, support for all Oracle Net configurations, and so on. Tools and applications that support the Oracle Database 10g server can be used to access heterogeneous data through the gateway.
Oracle transparent gateways can participate as a partner in multi-site transactions and two-phase commit. How this occurs depends on the capabilities of the underlying data source, meaning that a gateway can be implemented as any one of the following:
A full two-phase commit partner
A single-site update partner
A read-only partner
The deciding factors for implementing a gateway are the locking and transaction-handling capabilities of your target database.
All Oracle Database server products, including gateways, supply site autonomy. For example, administration of a data source remains the responsibility of the original system administrator. With site autonomy implemented, gateway products do not override the security methods of the data source or of the operating environment.
The integration of a data source through the gateway does not require any changes to be made to applications at the data source. As a result of this, the Oracle Database server technology is non-intrusive, providing coexistence and an easy migration path.
Functionally, gateway security is identical to that of an Oracle Database server, as described in the Oracle Database Administrator's Guide. Oracle Database server security is mapped to the data dictionary of the data source.
With the gateway, you can continue to develop your information systems without foregoing your investments in current data and applications. Access your Oracle and iWay Server data with a single set of applications and continue to use existing IBM applications to access your IBM data. You can also use more productive database tools and move to a distributed database technology without giving up access to your current data.
If you want to migrate to Oracle Database server technology and productivity, then the gateway allows you to control the pace of your migration. As you transfer applications from your previous technology to the Oracle Database server, you can use the gateway to move the iWay Server data into Oracle Database servers.
Oracle Transparent Gateway for iWay is a complete, ready-to-use solution combining proven technologies from Oracle and from Information Builders Incorporated (IBI). With Oracle Transparent Gateway for iWay, Oracle users on any platform can use SQL for read and write access of mainframe data stores without knowing the physical location of the data, the network protocol, or the operating system.
Figure 1-1 Oracle Transparent Gateway for iWay
Your existing z/OS systems can run undisturbed while Oracle applications access legacy data. As with the other Oracle gateways, Oracle Transparent Gateway for iWay makes access to non-Oracle data transparent to your Oracle applications. With no special programming, you can integrate legacy data and create true enterprise information systems. Oracle Transparent Gateway for iWay provides access to many databases and file systems, including those in the following list:
ADABAS, CA-Datacom, CA-IDMS, CA-IDMS SQL, FOCUS, IMS, ISAM, Model 204, QSAM, SUPRA, SYSTEM 2000, TOTAL, VSAM
For a complete list of the available iWay data adaptors, refer to your iWay documentation.
Oracle Transparent Gateway for iWay
Oracle Database 10g server on any platform
Information Builders, Inc. (IBI) iWay Server
Information Builders, Inc. (IBI) iWay Data Adaptors
Oracle Transparent Gateway for iWay and the iWay Server must run on z/OS. The Oracle Database 10g server can run on any Oracle-supported platform.
Using a database link, the gateway is identified to the Oracle Database 10g server. The database link is the same construct that is used to identify other Oracle Database server instances. Data that is stored in the target data stores is retrieved in the form of relational tables from the iWay Server. These iWay Server tables are referenced in SQL as:
If you create synonyms or views in the Oracle Database server, then you can refer to the iWay Server tables on the mainframe data server by using simple names as though the table were local to the Oracle Database server.
When the Oracle Database server encounters a reference to an iWay Server table, the applicable portion of the SQL statement is sent to the gateway for processing. Any host variables that are associated with the SQL statement are bound to the gateway and, therefore, are bound to the iWay Server.
The gateway is responsible for sending these SQL statements to the iWay Server for execution and for fielding and returning responses. The responses are data or messages. Any conversions between Oracle data types and iWay Server data types are performed by the gateway. The Oracle Database server and the application read and process only Oracle data types.
Not all SQL implementations are the same. The Oracle Database 10g server supports a larger set of SQL functions than are supported by the iWay Server. The Oracle Database 10g server and the gateway work together to convert SQL to a form compatible with the iWay Server.
The Oracle Database 10g server withholds functions that are not executable by the iWay Server and performs those functions after rows are fetched from the iWay Server. This is known as postprocessing. Refer to Chapter 9, "Developing Applications", for more information.