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Overview of the Oracle Application Server Integration Adapter for IMS/DB

This chapter introduces the Oracle Application Server Integration Adapter for IMS/DB. The Oracle Application Server Integration Adapter for IMS/DB is a plug-in component of Oracle Application Server ProcessConnect, enabling Oracle Application Server ProcessConnect to access IMS/DB data on IBM OS/390 or z/OS series operating systems.

This chapter contains the following sections:

Overview of Application Integration

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.

Overview of IMS/DB and Oracle Application Server Integration Adapter for IMS/DB

The Oracle Application Server Integration Adapter for IMS/DB is a plug-in component of Oracle Application Server ProcessConnect.

The Oracle Application Server Integration Adapter for IMS/DB models IMS/DB as a 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.

IMS/DB Data

IMS/DB (Information Management System - Data Base) is a high-performance hierarchical database.

The data access API to IMS/DB is called DL/I, which is a function by which the IMS/DB database can be traversed and operated on. Working with DL/I requires the caller to run under the control of IMS/DB. APIs are also available to enable access to IMS/DB from CICS and IMS/TM transactions.

The Oracle Application Server Integration Adapter for IMS/DB captures and maintains a metadata schema for IMS/DB by importing various IMS definition files such as a PSB file, DBD files and COBOL copybooks. These are transformed into mapping definition for Oracle Connect for IMS/DB on the OS/390 machine.

The Oracle Application Server Integration Adapter for IMS/DB 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 IMS/DB maps data structures, facilitating access to IMS/DB data from within Oracle Application Server ProcessConnect.

The Oracle Application Server Integration Adapter for IMS/DB 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.

IMS/DB does not have a concept of procedures or triggers. Applications that use IMS/DB may need to interact with Oracle Application Server ProcessConnect by sending it a native event. For inbound interactions the IMS/DB 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 Oracle Connect for IMS/DB will subscribe to a dedicated queue.

The Oracle Application Server Integration Adapter for IMS/DB includes the options to access IMS/DB data managed by CICS, IMS/TM or directly.

Accessing IMS/DB Data Under CICS

When IMS/DB records are defined under CICS, all access to the data is managed by CICS. The Oracle Application Server Integration Adapter for IMS/DB includes an option to access the IMS/DB data under CICS.

Accessing IMS/DB Data Under IMS/TM

When IMS/DB records are defined under IMS/TM, all access to the data is managed by IMS/TM. The Oracle Application Server Integration Adapter for IMS/DB includes an option to access the IMS/DB data under IMS/TM.

Accessing IMS/DB Data Directly

The Oracle Application Server Integration Adapter for IMS/DB includes an option to access the IMS/DB data directly.

Architecture of the Oracle Application Server Integration Adapter for IMS/DB

The Oracle Application Server Integration Adapter for IMS/DB includes the following components:

The IMS/DB adapter, which resides in Oracle Application Server ProcessConnect
Oracle Connect for IMS/DB, which resides on the OS/390 machine
A GUI-based configuration tool, called Oracle Studio for Legacy Adapters, which resides on a Windows platform.

Note:
Throughout this manual Oracle Studio for Legacy Adapters is referred to as Oracle Studio.

The components of the Oracle Application Server Integration Adapter for IMS/DB interact with each other, as shown in Figure 1-1 .

Figure 1-1 Architecture of the Oracle Application Server Integration Adapter for IMS/DB

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The IMS/DB adapter enables communication with Oracle Connect for IMS/DB on the OS/390 platform.

Oracle Connect for IMS/DB is comprised of three main components:

Daemon (a listener) - Responsible for managing and allocating server processes for client requests coming from Oracle Application Server ProcessConnect. Server processes can be started per client or kept in a pool for reuse. The daemon resides in a single address space and is executed as a started task.

See Also:
"Troubleshooting the Daemon" and Appendix D, "Daemon Configuration Settings" for details about the daemon
Database adapter - Provides the interaction definitions and input and output record schemas required to access the IMS/DB data
IMS/DB driver - Accesses the IMS/DB data based on database adapter interactions

Oracle Studio is used to model the adapter interactions and manage the back-end component.

Inbound Interactions

When IMS/DB runs under CICS or IMS/TM, 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 IMS/DB will subscribe to a dedicated queue.

The Oracle Application Server Integration Adapter for IMS/DB provides the following ways to send an inbound interaction:

Invoking a special CICS transaction
Invoking a special IMS/TM transaction
Using an API from a COBOL program

Integrating Oracle Application Server ProcessConnect with the Adapter for IMS/DB

Oracle Application Server Integration Adapter for IMS/DB is fully integrated with Oracle Application Server ProcessConnect, both during the modeling and runtime phases.

The Modeling Phase

The Oracle Application Server Integration Adapter for IMS/DB is integrated with Oracle Application Server ProcessConnect as follows:

Modeling the Oracle Application Server Integration Adapter for IMS/DB is performed using Oracle Studio. This step includes modeling both the metadata for the IMS/DB data source and modeling inbound and outbound interactions as required.

See Also:
"Modeling the IMS/DB Adapter Using Oracle Studio"
After the Oracle Application Server Integration Adapter for IMS/DB has been modeled in Oracle Studio, the integration between the adapter and the application in Oracle Application Server ProcessConnect is modeled. Within Oracle Application Server ProcessConnect you define a delivery channel for the adapter and then add interactions from the list modeled using Oracle Studio.

See Also:
Oracle Application Server ProcessConnect User's Guide

Runtime

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 IMS/DB are handled by Oracle Connect for IMS/DB on the OS/390 machine. The IMS/DB 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.

Modeling the IMS/DB Adapter Using Oracle Studio

Oracle Studio is used to model and manage the Oracle Application Server Integration Adapter for IMS/DB.

Oracle Studio uses perspectives enabling you to focus specific information necessary to model the Oracle Application Server Integration Adapter for IMS/DB.

The following perspectives are available:

The Configuration Perspective

Use the Configuration perspective to define access to the IBM OS/390 machine and to IMS/DB data on the machine.

The Metadata Perspective

Use the Metadata perspective to model the following:

The Oracle Application Server Integration Adapter for IMS/DB interactions and the expected inputs and output
The IMS/DB data source records and the fields in these records

The Metadata Import Perspective

Assuming that metadata for the IMS/DB data source is available, use the Metadata Import perspective to import this information for use by Oracle Connect for IMS/DB to create outbound interactions.

The Runtime Manager Perspective

Use the Runtime Manager perspective to troubleshoot Oracle Connect for IMS/DB by monitoring daemon activity on the OS/390 machine.

1 Overview of the Oracle Application Server Integration Adapter for IMS/DB