Here are some general considerations for importing and exporting data or table objects.
The QMF IMPORT DATA command appears to store the data in the QMF temporary storage area and display the report on the screen. Actually, only a portion of the data is stored and displayed. The file, data set, or CICS data queue remains open and allocated to QMF. QMF reads records when the user scrolls through the file, data set, or CICS data queue.
This connection is maintained until the data object is replaced or reset, or QMF has read all the records. At this point, the file, data set, or CICS data queue is closed and is no longer considered allocated to QMF. This means that an application should not attempt to delete or alter a file, data set, or CICS data queue allocated to QMF with an IMPORT DATA command. The application needs to either start using another data source or empty the QMF temporary data storage area (RESET DATA) before it tries to alter or delete a data set it has been reading.
During the execution of the IMPORT command, QMF does not lock the file, data set, or CICS data queue while it is being read. It does not take steps to prevent the file, data set, or CICS data queuefrom being altered while it is being read. If the file, data set, or CICS data queue is erased or altered in any way before QMF has finished reading it, the results are unpredictable and can cause a system error.
An incomplete data prompt can occur when QMF needs to complete the object and there isn't enough storage for the data object. QMF needs to complete the data object if, for example, you requested the export of an object to the same file, data set, or CICS data queue. This situation implies that you previously performed an IMPORT DATA command from the same file, data set, or CICS data queue now named on the EXPORT command. For more information about the incomplete data prompt and actions to take, see either:
When you export a data or table object using the QMF format or the binary form of the IXF format (OUTPUTMODE=BINARY), the data is in a raw binary form. However, when you use the character form of IXF (OUTPUTMODE=CHARACTER), the exported data is in EBCDIC form. Exported data for form, report, procedure, and SQL query objects is also in EBCDIC form.
Application programs written in languages such as PL/I, COBOL, and assembler can usually read and process binary data faster and more efficiently than character data. Interchanging data from one IBM product to another is more efficiently done in binary. However, if your application programs are written in REXX, or if you're processing the data with an editor, you'll find EBCDIC (character) data to be more efficient.
After QMF imports data from a file, data set, or CICS data queue, QMF displays the report panel and a confirmation message. If the file, data set, or CICS data queue contains format errors, QMF does not display the report panel; instead, QMF displays an error message on the object panel that was current before QMF processed the IMPORT command. However, if the current object panel was the Report panel, and QMF finds errors in the imported data, QMF displays the Home panel and an error message.
Unlike the form object, when a data or table object is imported, the format of the input file, data set, or CICS data queue must be precisely the same as the format of the output file, data set, or CICS data queue that would be generated if the same object were exported using the EXPORT DATA or EXPORT TABLE command.
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