Unlocked Records and the SORT Statements
Now compare the following two applications, where the found set is not locked because the FDWOL (FIND WITHOUT LOCKS) statement is used to create the found set labelled ALL. Everything discussed here applies if the sort was operating against a record list, which by definition is not locked.

SORT RECORDS application

BEGIN
ALL:  FDWOL ADMIT.DATE = 20071101
      END FIND
SRT1: SORT RECORDS IN ALL BY CITY
FR SRT1
  PRINT PATIENT.ID AND DIAGNOSIS -
  AND PHYSICIAN AND CITY AND STATE 
END

SORT RECORD KEYS application

BEGIN
ALL:  FDWOL ADMIT.DATE = 20071101
      END FIND
SRT1: SORT RECORD KEYS IN ALL BY CITY
FR SRT1
  PRINT PATIENT.ID AND DIAGNOSIS -
  AND PHYSICIAN AND CITY AND STATE 
END

• The SORT RECORDS application results do not reflect changes made while processing because the temporary records sorted and saved on CCATEMP pages are not updated by concurrent update applications. Of course, the underlying Table B base records are updated. However, since the data from those records has already been extracted and copied to CCATEMP pages for sort processing, subsequent updates to the underlying Table B base records are not seen by that application’s FR SRT1 loop.
• The SORT RECORD KEYS application results might reflect changes to the underlying Table B base records. Since the data from these records is revisited during the FR SRT1 loop, updates made by other users to a record not yet processed by the FR SRT1 loop will be seen in the PRINT output. This could lead to unexpected results especially if some of the fields used in the find criteria change before your report completes.

Unexpected results
For example, you may want to produce a report including only Volkswagons, only to discover that some of those Volkswagons have turned into Mercedes! That could happen in the following example where the FDWOL found set could have MAKE changed in some of the records before they are processed by the FOR EACH RECORD loop. This is a somewhat far-fetched example to illustrate the point.

BEGIN
ALL: FDWOL MAKE = VOLKSWAGON
     END FIND
SRT1: SORT RECORD KEYS IN ALL BY YEAR
FOR EACH RECORD IN SRT1
  PRINT YEAR AND MAKE AND VIN AND MODEL
END

If another request runs before or during the FOR EACH RECORD IN SRT1 loop and changes some of the records in the found set ALL from MAKE=VOLKSWAGON to MAKE=MERCEDES before those records are printed, then this report may print some Mercedes records even though the found set originally included only Volkswagons. When using FDWOL, keep in mind that your found set, since it is not locked, could end up being a collection of records you don’t want or expect because the fields used as find criteria in the FDWOL may have changed by the time you process the records in a subsequent FOR loop.

Loading PC-Format Data Finishing Details
By Tym Stegner

In my previous article, Loading PC-Format Data into System 1032, we diagnosed a LOAD problem caused by a non-VMS data file, and began the process to convert this data into a form that System 1032 can read. In this article, we will continue the process, including:

Determining Record Length
The previous article concluded with my explanation of how to use the VMS CONVERT command with an FDL file to translate a STREAM format file into a VARIABLE format file. This article begins with the next step: to determine the appropriate record length.

The RD we plan to use to load this data file has a record length of 591 characters. (Note: to see the record length of an RD, use the command SHOW RD <name> FIELD COLUMN, then look at the last entry. Usually this will be the full record length.)

At my request, the customer, who originally asked how to load this large text file, modified the SIZE quality in the RECORD section of the FDL file to be this length:

  +RECORD
+        BLOCK_SPAN              yes
+        CARRIAGE_CONTROL        carriage_return
+        FORMAT                  variable
+        SIZE                    591

When the file was modified, the customer used that FDL file with the CONVERT command to translate the data file, then tried to load it into the dataset from System 1032. To reduce the time necessary to test the updated file, I suggested the use of the MAXIMUM option in the LOAD command, to limit the number of records to be read in to only the first 10 records.

Unfortunately, there was still a problem. When the CONVERT command was attempted, the following error occurred:

 Convert-I-RTL, record longer than maximum record length.

Consulting HELP/MESSAGE, I found the following explanation:

 $ HELP/MESSAGE/FACILITY=CONVERT  RTL
 RTL,  record longer than Maximum Record Length
  Facility:     CONV, Convert Utility
  Explanation:  The record from the input file is longer than the 
                maximum record length specified in the output file. 
                This is an exception condition; the record will not 
                be written to the output file. If the /EXIT qualifier 
                is specified, processing will stop.
  User Action:  Specify the /TRUNCATE qualifier.

This suggested to me that the SIZE quality we specified in the FDL file was not adequate. Although 591 bytes is the amount of data to be read into the dataset, it is not necessarily the length of the record in the input file.

Back to the beginning
It seemed as though we had just come back to the beginning with no forward progress. We needed to examine the record to find out how long it actually is, but we could not do that, because we could not open the file in the editor. If we could open the data file, we could inspect a record and check for a LineFeed character, which marks the end-of-record.

So, we discussed two approaches:

Extracting Records
So, how can we get a few records out of the file for inspection, when we cannot use the editor to open the file? The DCL command language came to our rescue. The following short DCL program can extract the first 10 records from the file supplied as the first parameter:

Summary
This article concludes the processing of a STREAM file into a VARIABLE format file, suitable for reading into System 1032. As the original file was much too large to be converted using the editor, as was the practice at this site, the CONVERT command and an FDL file were used to reformat the STREAM file into a fixed length VARIABLE format file.