Chapter 8: Importing Database Definitions

In this chapter, you learn about the Importer Facility and import a database.

Learn about the Importer Facility

Goal

In this section, you learn about importing database definitions using the APS Importer Facility.

The Importer Facility translates information about your database definitions and their associated copybook records into a format usable for generating and precompiling through APS. The APS Importer Facility transfers database information such as data definitions and/or database subschemas to make them available to your APS programs. You can import IMS PSBs and DBDs, SQL DDL statements, VSAM files, and IDMS subschemas.

If necessary, your APS programs can access multiple database targets. In that case, you can create and import two separate subschemas. For example, you can import both VSAM file information and a subschema for SQL, and then combine the two into one subschema.

When you import your database definitions, the Database Definition Interface (DDI) formats the database information to use with APS programs. The Importers:

Extract information from your database definition.
Load extracted information into the DDIFILE.
Generate a DDISYMB file for use by Online Express and the appropriate APS Generator.
Generate record description copybooks of SQL DDL statements that contain database and COBOL descriptions of each table or view in the imported subschema.

To import the VSAM file definitions for this tutorial, you first write DDI statements and then import the file definitions. The DDI statements associate the VSAM files with their COBOL copylib record descriptions.

The VSAM Importer translates information about VSAM files and their associated copylib record into a format usable for generating and precompiling through APS. For each VSAM file record, there is a copylib file that contains a COBOL record description. These copylib files are in your project.group.COPYLIB.

We imported the VSAM database for you. You can verify the import process.

Verify the Database Import

Goal

In this section, you verify the import process for this tutorial by printing the Program DB/DC Report, one of the reports provided by APS.

APS provides a set of reports that help you understand your application and its various components. You can use these reports as you develop an application to determine the status of your work and the tasks left to complete. Some reports help you to troubleshoot problems in an application that you are developing, or to determine the impact of a proposed change. Others help you to verify the results of your work. Once you have fully implemented an application, use the APS reports to document it so that developers who later maintain or enhance the application can easily understand it in detail.

One of the reports most-used by developers is the Program DB/DC Report, which documents the screens and subschemas used by a program.

The Program DB/DC Report has three sections:

Database views, showing any of the following applicable to your database target:
- Record names of the root and each dependent segment
- Segments in hierarchical sequence, indented to show each segment's level in the data base
- Functions (PROCOPTS) that can be performed for each segment
- Key and sequence fields for accessing each record
- VSAM file descriptions
Record I/O areas, showing the COBOL I/O areas for the database and file records
Screen I/O areas, showing the COBOL I/O areas for up to 20 specified screens

Procedure

Start this procedure where the last one ended -- in the APS Main Menu.

On the Main Menu, type 2 in the Option field and press Enter. The Dictionary Services screen displays.

Figure 8-1: Access the Documentation Facility
To select Actions Documentation Facility, type 2 in the Option field and press Enter. The Documentation Facility screen displays, where you select the report to print.

Figure 8-2: Select Reports that Document the Application
To select the Program DB/DC Report, type 5 in the Option field and press Enter. The report selection screen displays, where you enter the selection criteria.

Figure 8-3: Request the Report for the Program Subschema
Type apsupd in the Program field.
Type apsupd in the PSB/Subschema field.
Press Enter to execute the report and submit a batch job that prints it.
After the report has executed, you can optionally view it online. To do so, type the tso sdsf IBM command in the Command field and press Enter.
Press F3 repeatedly until you return to APS Main Menu.

Checkpoint

The VSAM file report is generated. You can now define the program specifications in Online Express.

Hints

APS provides a number of other reports describing application entities such as applications, screens, data structures, programs, scenarios, and report mock-ups. Through criteria you select, you can see the reports in a number of categories and formats.