The LINEFILE option specifies that the DBRM statement number field should encode both the file number and the line number for each SQL statement.
.-LINEONLY-. >>-+-LINEFILE-+------------------------------------------------><
When the LINEFILE option is in effect, the DBRM statement number field encodes both the file number and the line number for each SQL statement. In particular, the file number will be in the first 12 bits of the statement number and the line number will be in the remaining 20 digits.
When the LINEONLY option is in effect, the DBRM statement number field just encodes the line number for each SQL statement.
As in the rest of the compile processing, the compiler assigns the number 0 to the primary source file, the number 1 to the first include file, etc. So, if all the SQL statements are in the primary source file, there is no difference between LINEFILE and LINEONLY.
For compatibility, LINEONLY is the default.