This chapter describes the features available in Mainframe Express that enable you to access mainframe-based files from your Mainframe Express projects. The section below shows how you can configure Mainframe Express to work with files while they are still on the mainframe, while the section Downloading IMS Databases describes the steps involved in moving an IMS database from a mainframe to a PC.
Mainframe Access is a suite of Micro Focus tools that enables you to access files residing on a mainframe. Mainframe Express includes the client software for Mainframe Access, so if you have installed the Mainframe Access server software on your mainframe, you can use Mainframe Express projects to access mainframe files as easily as PC files.
Before you can access mainframe files using Mainframe Access, you need to have installed and configured a number of options. You must perform the following operations:
The Server Access Configuration utility lets you define a number of nodes, where a node can be a mainframe or Fileshare server. As Mainframe Express can work with multiple nodes in the same project, you could, for example, implement a project that uses one node for data files, and a second node for your development work (to which you could submit compilation and link actions).
The process of downloading an IMS database from a mainframe to a PC consists of three stages:
These stages are described in the following sections.
You must unload the IMS database into a sequential file with variable-length records. The file must contain one record for each segment and each record must contain the record length, segment name, and segment data in fixed positions. Two utilities for creating a suitable sequential file are:
The standard IBM unload utility creates a sequential file with a variable-length record for each segment. In each record, the segment name begins in position 7 and the segment data begins in position 36.
The IMSDBUV utility is supplied with Mainframe Express. You can transfer it to the mainframe where it runs in IMS/ESA as a batch program. It retrieves segments from a database. For each segment, it creates a variable-length record containing record length, segment name, and segment data.
IMSDBUV can also add header and trailer records to the file to describe the file's contents and, for example, the compression routine used.
You can use the Mainframe Access Drag and Drop facility to download and automatically load the IMS database for you, as follows:
Alternatively, you can use any file transfer utility that supports binary file transfer to transfer the sequential file to the PC. A binary file transfer does not perform conversion from the EBCDIC character set to ANSI and does not add carriage return or line-feed (CR/LF) record delimiters.
If you have used the Mainframe Access Drag and Drop facility to download the IMS database, the reload has already been done.
If you used another file transfer utility, you can use the IMSDBU utility that is supplied with Mainframe Express to load the database from a variable-length sequential file. To use IMSDBU from the Mainframe Express IDE, do the following:
For more information, see the section IMSDBU - Data Management in the chapter Developing IMS Applications in your User's Guide.
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