Describing an IMS Database to the IMS Java Function

In order for a Java application to access an IMS database, it needs information about the database. This information is contained in the PSB (program specification block) and in DBDs (database descriptions), which you must first convert into a form that you can use in the Java application: a subclass of the com.ibm.ims.db.DLIDatabaseView class called the IMS Java metadata class. The DLIModel utility generates this metadata from the IMS PSBs, DBDs, COBOL copybooks, and other input specified by utility control statements.

In addition to creating metadata, the DLIModel utility also:

• Generates XML schemas of IMS databases. These schemas are used when retrieving XML data from or storing XML data in IMS databases.

• Incorporates additional field information from XMI input files that describe COBOL copybooks.

• Incorporates additional PCB, segment, and field information, or overrides existing information.

• Generates a DLIModel IMS Java Report, which is designed to assist Java application programmers. The DLIModel IMS Java Report is a text file that describes the Java view of the PSB and its databases.

• Generates an XMI description of the PSB and its databases.

The DLIModel utility can process most types of PSBs and databases. For example, the utility supports:

• All database organizations except MSDB, HSAM, SHSAM, and GSAM

• All types and implementations of logical relationships

• Secondary indexes, except for shared secondary indexes

• Secondary indexes that are processed as standalone databases

• PSBs that specify field-level sensitivity

The DLIModel utility is a Java application, so you can run it from the UNIX System Services prompt, or you can run it using the z/OS-provided BPXBATCH utility.

Figure 18-1 on page 313 shows the inputs to and outputs from the DLIModel utility.

Figure 18-1. DLIModel Utility Inputs and Outputs

Related Reading: For more information about the DLIModel utility, see IMS Version 9: Utilities Reference: System.