Query Management Facility - IBM Mainframe

Query Management Facility (QMF) is an interactive facility offered by IBM to supplement SPUFI. Like SPUFI, QMF enables you to dynamically submit SQL statements that retrieve and modify data in DB2 tables. Having read familiarized with SQL's Data Manipulation Language (DML), you are well on your way to also knowing QMF. Data Definition and Data Control statements may also be submitted through QMF, but its main use is as a query tool with DML SELECT statements. QMF differs from SPUFI in two major ways. First, it is meant to be more of an end-user facility than SPUFI, which is designed solely for DP personnel, and second, QMF provides sophisticated report formatting facilities.

QMF is designed for a variety of users and their differing needs. For DP personnel, QMF offers 4GL-type productivity gains. The combination of QMF and SQL makes it easy to look at test data in different ways, e.g., generating control totals, counting the number of distinct values, etc. It is also possible to create production reports in a fraction of the time it would take with COBOL or any other 3GL programming language. Modifications to reports are equally easy. It must also be noted, however, that as with any other 4GL report writer, QMF cannot provide as much flexibility as a COBOL report program and furthermore, QMF will have more overhead. Your management and users will have to decide if the reduced development and maintenance costs merit a compromise in report format flexibility and operational overhead. QMF can be used to replace CICS inquiry programs, but here, too, the operational overhead and limited flexibility must be balanced with the pluses.

QMF is also meant to be a tool for end-user ad hoc queries, although the degree to which it succeeds in this is open to debate. While QMF's basic options are not hard to learn, can a user easily pick up the SQL syntax required for formulating a query? Although SQL is a higher-level language than COBOL, it is still basically a programmer's language. To help with this, QMF provides two alternatives to SQL for writing queries, QBE (Query By Example) and Prompted Query. The choice of language, QBE, SQL, or Prompted Query, is made on the QMF Profile Panel, which is reached from the Home Panel.

How you get to QMF will depend on how it has been installed at your site. It may be a choice on your ISPF Menu, a choice on one of its submenus, a CLIST, etc. When you invoke QMF, you are presented with the QMF Home Panel. From there you will navigate to other QMF panels through a combination of commands and PF keys. The QMF Home Panel contains the QMF logo, the version and copyright details and so on. There is a command line at the bottom and a set of PF key assignments above it. Messages from QMF will appear above the command line. From this panel you can go to the panels associated with writing queries (PF6 = QUERY), formatting the output of queries (PF9=FORM), writing procedures (PFIO = PROC), viewing a formatted report (PF12 = REPORT), modifying your QMF profile (PF11 = PROFILE), or viewing the output of a query as a chart (PF5 = CHART). The ability to display charts depends on your installation's configuration of software and hardware. The other PF keys on the Home Panel are shorthand ways of executing the QMF commands HELP, RETRIEVE, LIST, and SHOW.

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