READ statement problem

, ,
1

I need to use a READ statement but need to use “OR” and WHERE clauses but doesnt work. Im using FIND now but our DBA suggests to use READ…example

FIND FILE-1 with DESCRIPTOR-DATE1 = #start-date thru #end-date OR
DESCRIPTOR-DATE2 = #start-date thru #end-date
WHERE Indicator = “C”
…
END-FIND

But when i use READ instead of FIND…i encounter an error. Can someone help?
Thanks!

2

If your DBA is suggesting a READ, then he should suggest how to code it, too. :wink:

FIND returns a set of records based on some logical criteria. READ returns a sequence of records - in your example, by a key, but physical and internal sequences are also possible. FIND syntax allows a combination of descriptors; READ does not.

If your logical condition was an AND, then you could code

READ FILE-1 BY DESCRIPTOR-DATE1 FROM #start-date THRU #end-date 
         WHERE DESCRIPTOR-DATE2 =    #start-date THRU #end-date 
           AND Indicator        =    "C"

“WHERE DESCRIPTOR-DATE2” limits the records to a subset of DESCRIPTOR-DATE1. Can you
guarantee that all records with the specified DESCRIPTOR-DATE2 values also contain the
specified DESCRIPTOR-DATE1 values? With an OR condition, you need a descriptor which
will return all values specified for both DESCRIPTOR-DATE1 and DESCRIPTOR-DATE2.

Here’s a simpler example.

FIND file with SURNAME = 'ZBROG' 
            OR FIRSTNM = 'RALPH'

This returns all ZBROGs and all RALPHs.

If you were certain that all RALPHs were ZBROGs, then you could code

READ file BY SURNAME FROM 'ZBROG' THRU 'ZBROG' 
       WHERE FIRSTNM =    'RALPH'

But if RALPH SMITH exists on the file, the FIND will return this record, but the READ
will not. You need a descriptor which returns all ZBROGs and all RALPHs, and then you
can ignore those records which do not satisfy both criteria.

3

Mikko,

You cannot do what you needed in a single READ
You may have to use two read statements and store the values in workfile and merge the two files and then use the work file for processing.

READ FILE-1 BY DESCRIPTOR-DATE1 FROM #start-date THRU #end-date
WRITE WORK 1 #REC
END-READ

READ FILE-1 BY DESCRIPTOR-DATE2 FROM #start-date THRU #end-date
WRITE WORK 1 #REC
END-READ

Regards
Vasanth

4

Seems like a lot of extra work to write a work file. Why not…

READ file BY DESCRIPTOR-DATE1 FROM date1 THRU date2
   PERFORM PROCESS-FILE-RECORD
END-READ

READ file BY DISCRIPTOR-DATE2 FROM date3 THRU date4
   PERFORM PROCESS-FILE-RECORD
END-READ

–Jerome

5

The disadvantage of two READs: If the periods of time are overlapping each other, you will process some records twice…
The advantage is perhaps: It could be faster and you don’t need space on the Adabas WORK-area.