II09058: INCOMPATIBLE COMPARISON FOR DATA TYPE-DECIMAL ON DB2/MVS VS. THE DOUBLE PRECISION HOST VARIABLE ON WORKSTATION C++.

APAR status

• Closed as canceled.

Error description

• This INFO APAR will document the incompatible data type
  comparison for Data Type-DECIMAL on Host vs. the
  Double Precision host variable on Workstation C++.
  .
  .
  The problem occurs when comparing 2 floating point numbers, one
  converted from a decimal column in the DB2/MVS or DB2/VM table,
  another converted from an 8 byte double precision floating point
  number coming from a C application on the PC. The difference is
  in the very last bit in the number being represented. For some
  floating point numbers, the number coming from the PC is larger
  by the last significant bit. This could have to do with how the
  IEEE floating point format is defined as compared to the 370
  floating point numbers. For example;
  
  (1) On the PC side:
  1240.21 ---> A4703D0A D7609340 for IEEE floating point
               representation.
          ---> 434D835C 28F5C290 converted to 370 floating point
               from IEEE floating point representation.
  
  (2) On the 370 side:
  1240.21 (Decimal 13,2) ---> 434D835C 28F5C28F for 370 floating
                              point representation.
  So even though the 2 numbers are very close, but they are not
  equal. Therefore, the EQUAL predicate in the WHERE Clause from a
  SELECT of the table on host could not be satisfied in this case.
  .
  Possible solutions:
  (1) Use Workstation COBOL with DECIMAL host variables.
  (2) DB2/MVS V4 has a conversion function that will
     convert CHAR (Char. representation of a decimal number)
     variables to decimal.
  e.g.        COL1  = DECIMAL(:HV,13,2)   <V4.1 only>
         CHAR(COL1) =         :HV
       DIGITS(COL1) =         :HV
  Note: column = expression  and  expression = value are not
  indexable (see DB2 Admin Guide (SC26-4888-00 page 7-235,
  Table 171. Predicate Types and Processing)
  ...
   --See V4 DB2 SQL Reference (SC26-3270-00) for DECIMAL and
   DIGITS or CHAR Scalar Functions.
  
  (3) The application program could use SQLDA with SQLTYPE 484/485
      to specify a decimal value (conversion to a C language data
      type would have to be handled by the application).
         See DB2/MVS V3.1 SQL REFERENCE APPENDIX C P405 and
      APPLICATION PROGRAMMING GUIDE P3-47 to 3-57 for SQLDA and C
      coding guidelines. For DB2/VM refer to DB2/VM V3.4
      APPLICATION PROGRAMMING MANUAL P282 in APPENDIX B.
  ...
  ...
  Additional Search Arguments: DB2 5740xyr00 r230 r310 r410
  

Local fix

Problem summary

Problem conclusion

Temporary fix

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Fix information

Applicable component levels