This page describes how to compare fixed width text files with database tables using DTM Data Comparer.
[fixed.txt] MaxScanRows=0 CharacterSet=ANSI DecimalSymbol=. Format=FixedLength Col1=Year Short Width 4 Col2=Month Short Width 3 Col3=Day Short Width 3
The sample file "fixed.txt" has 3 columns (Year, Month and Day), the data type is "Short" for all. Column widths are 4, 3 and 3.