Re: Want to check, whether a field existing in file or not.

Check file SYSCOLUMNS in library QSYS2 and file QADBXREF in library QSYS.  They
have helped me in doing fast researches like this.
Look at this Query/400 definition I use:

 Selected files
   ID     File           Library       Member        Record Format
   T01    SYSCOLUMNS     QSYS2         *FIRST        SYSCOLUMNS
   T02    QADBXREF       QSYS          *FIRST        QDBXREF

 Join tests
   Type of join  . . . . . . . . . . . . . Matched records
   Field              Test              Field
   SYS_TNAME          EQ                T02.DBXFIL

 Select record tests
   AND/OR   Field             Test     Value (Field, Numbers, or 'Characters')
            SYS_CNAME         EQ       'FIELDNAME'
    AND     SYS_DNAME         EQ       'LIBRARYNAME'
    AND     DBXATR            EQ       'PF'

 Ordering of selected fields
   Field           Sort      Ascending/  Break  Field
   Name            Priority  Descending  Level  Text
   T01.SYS_TNAME   10        A           1      File name
   T01.SYS_DNAME                         1      Library name

 Ordering of selected fields (continued)
   Field           Sort      Ascending/  Break  Field
   Name            Priority  Descending  Level  Text
   T02.DBXTXT                            1      File text

 Report column formatting and summary functions
   Summary functions:  1-Total, 2-Average, 3-Minimum, 4-Maximum, 5-Count
Overrides
   Field           Summary    Column                                Dec  Null
Dec  Numeric
   Name            Functions  Spacing  Column Headings         Len  Pos  Cap
Len  Pos  Editing
   T01.SYS_TNAME              0        SYSTEM_TABLE_NAME        10
   T01.SYS_DNAME              2        SYSTEM_TABLE_SCHEMA      10
   T02.DBXTXT                 2        FILE                     50
                                       TEXT
 Report breaks
   Break  New   Suppress   Break
   Level  Page  Summaries  Text
   1      No    No

 Selected output attributes
   Output type . . . . . . . . . . . . . . Database file
   Form of output  . . . . . . . . . . . . Summary only
   Line wrapping . . . . . . . . . . . . . No

 Database file output
   File  . . . . . . . . . . . . . . . . . QQRYOUT
     Library . . . . . . . . . . . . . . . PETERVI
   Member  . . . . . . . . . . . . . . . . *FILE
   Data in file  . . . . . . . . . . . . . Replace file
   For a new file:
     Authority . . . . . . . . . . . . . . *LIBCRTAUT
     Text about
       the file  . . . . . . . . . . . . .
   Print definition  . . . . . . . . . . . No

 Output file record format
   Output record length  . . . . . . . . .    72
   Output CCSID value  . . . . . . . . . .    37
   Field list:
     Field          Begin   Len  Dec   Null  Data Type            Text
     BREAKLVL           1     1              Character            BREAK LEVEL
     OVERFLOW           2     1              Character            OVERFLOW FLAG
     SYS_TNAME          3    10              Character            File name
     SYS_DNAME         13    10              Character            Library name
     DBXTXT            23    50              Character            File text

Peter Vidal
Pall Aeropower Corp.
SR Programmer Analyst
WWW.Pall.com

"A good player makes himself look good; a great player makes the team look
good."
Author unknown