10g (9.0.4)
Part Number B10457-01
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| Oracle® Application Server Integration Adapter for VSAM Installation and User's Guide 10g (9.0.4) Part Number B10457-01 |
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This chapter introduces the Oracle Application Server Integration Adapter for VSAM. The Oracle Application Server Integration Adapter for VSAM is a plug-in component of Oracle Application Server ProcessConnect, enabling Oracle Application Server ProcessConnect to access VSAM data on IBM OS/390 or z/OS series operating systems.
This chapter contains the following sections:
When business applications need to communicate with each other, the output from one application is not always understandable by the other application. Application adapters enable different applications to interoperate.
Adapters for application integration address a mismatch between the integrating interface of a source or target application and the integration infrastructure, such as Oracle Application Server ProcessConnect. Simple adapters only exchange data using an API, but complex adapters can also do transformations (such as SQL to XML), as well as deal with exception conditions. Therefore, adapters are a combination of modeling tools and runtime software that act as "glue" to link applications, considered as sources or targets (or both), to the integration infrastructure that transports, translates, transforms, and routes data between systems. On the one hand, an adapter deals with a group of touchpoints (one or more entry/exit points, collectively an interface) for a source or target; on the other hand, an adapter links to the integration infrastructure. This means that adapters generally have two interfaces - one that is native to the source or target application and the other that is native to the integrating infrastructure. Adapters perform a variety of key tasks, including recognizing events, collecting and transforming data, and exchanging data with the integration infrastructure. They also handle exception conditions, and can often dynamically (or with minor reconfiguration changes) accommodate new revisions of back-end applications.
Each task performed by the adapter is defined as an interaction. Interactions that are initiated by the source or target application are referred to as inbound interactions. Interactions that are initiated by the integrating infrastructure are referred to as outbound interactions.
The Oracle Application Server Integration Adapter for VSAM is a plug-in component of Oracle Application Server ProcessConnect.
The Oracle Application Server Integration Adapter for VSAM models Virtual Sequential Access Method (VSAM) as a simple database with an SQL front end. The adapter is native to the data source and OS/390, providing direct access that results in improved performance.
VSAM is an IBM disk file storage scheme first used in S/370 and VS (virtual storage). VSAM comprises three access methods:
All of the VSAM access methods (KSDS, RRDS and ESDS) are supported by the adapter.
VSAM has no built-in metadata schema although a VSAM file does include information about its type (KSDS, RRDS, or ESDS) and its index definition (KSDS only). Typically, VSAM is used by COBOL programs - either standalone (also known as batch programs) or CICS transactions. The VSAM record definitions are typically maintained within the COBOL code as COBOL copybooks.
The Oracle Application Server Integration Adapter for VSAM includes the following features:
The Oracle Application Server Integration Adapter for VSAM captures and maintains a metadata schema for VSAM by importing COBOL copybooks and transforming them into mapping definitions for Oracle Connect for VSAM on the OS/390 machine and by associating the data structures with specific physical files.
The Oracle Application Server Integration Adapter for VSAM has a full-fledged query processor and optimizer that executes SQL against the VSAM data with full support for VSAM datatypes such as arrays.
The Oracle Application Server Integration Adapter for VSAM uses an enterprise application integration (EAI) model. Users of a requesting application can model the interactions that they want implemented, specifying what each interaction does, when it occurs and the inputs and outputs expected for each interaction. Moreover, the Oracle Application Server Integration Adapter for VSAM maps data structures, facilitating access to VSAM data from within Oracle Application Server ProcessConnect.
Since VSAM is viewed as a database, the Oracle Application Server Integration Adapter for VSAM implements outbound interactions as parameterized SQL with the parameters forming the input record, and with the output (in cases where there is an output) aggregated into an XML document forming the output record.
VSAM does not have a concept of procedures or triggers. Applications that use VSAM may need to interact with Oracle Application Server ProcessConnect by sending it a native event. For inbound interactions the VSAM application uses a special API to send a native event to a queue running on the mainframe and the adapter subscribes to that queue for inbound event handling. Typically, each application associated with an Oracle Connect for VSAM will subscribe to a dedicated queue.
The Oracle Application Server Integration Adapter for VSAM includes the options to access VSAM data managed by CICS or directly.
When VSAM records are defined under CICS, all access to the data is managed by CICS. The Oracle Application Server Integration Adapter for VSAM includes an option to access the VSAM data under CICS.
When VSAM records are not defined under CICS, the Oracle Application Server Integration Adapter for VSAM includes an option to access the VSAM data directly. This option can also be used to improve performance when the VSAM records are managed by CICS but access to them is for read only, and there is no risk that there are changes buffered by CICS while the read is performed.
The Oracle Application Server Integration Adapter for VSAM includes the following components:
The components of the Oracle Application Server Integration Adapter for VSAM interact with each other, as shown in Figure 1-1.
The VSAM adapter enables communication with Oracle Connect for VSAM on the OS/390 platform.
Oracle Connect for VSAM is comprised of three main components:
Oracle Studio is used to model the adapter interactions and manage the back-end component.
When VSAM runs under CICS, it can interact with Oracle Application Server ProcessConnect by sending it a native event. The native event is sent to a queue running on the mainframe and the adapter subscribes to that queue for inbound event handling. Typically, each application associated with Oracle Connect for VSAM will subscribe to a dedicated queue.
The Oracle Application Server Integration Adapter for VSAM provides the following ways to send an inbound interaction:
Oracle Application Server Integration Adapter for VSAM is fully integrated with Oracle Application Server ProcessConnect, both during the modeling and runtime phases.
The Oracle Application Server Integration Adapter for VSAM is integrated with Oracle Application Server ProcessConnect as follows:
At runtime, the interactions specified in the Oracle Application Server ProcessConnect application are executed.
For outbound interactions, the interactions for the Oracle Application Server Integration Adapter for VSAM are handled by Oracle Connect for VSAM on the OS/390 machine. The VSAM data source is queried and the results of this query are returned to Oracle Application Server ProcessConnect.
For inbound interactions, the interactions are initiated on the OS/390 machine and sent to Oracle Application Server ProcessConnect.
Oracle Studio is used to model and manage the Oracle Application Server Integration Adapter for VSAM.
Oracle Studio uses perspectives enabling you to focus specific information necessary to model the Oracle Application Server Integration Adapter for VSAM.
The following perspectives are available:
Use the Configuration perspective to define access to the IBM OS/390 machine and to VSAM data on the machine.
Use the Metadata perspective to model the following:
Assuming that metadata for the VSAM data source is available in a COBOL copybook, use the Metadata Import perspective to import this information for use by Oracle Connect for VSAM to create outbound interactions.
Use the Runtime Manager perspective to troubleshoot Oracle Connect for VSAM by monitoring daemon activity on the OS/390 machine.
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