Hi Suneel,
When you are reading the flat file it should be fields as character data type only!
Read the file with all character type fields only ( even your ERFMG).
Store the file contents in one internal table and declared one more internal table type of your Z table.
Move the entries to Z internal table and insert the entries.
* Make it the internal table file read as below!
TYPES: BEGIN OF ty_zdsl,
* mandt TYPE zdsl-mandt,
* werks TYPE zdsl-werks,
* pallet_id TYPE zdsl-pallet_id,
* matnr TYPE zdsl-matnr,
* erfmg(20) TYPE c,
* uom TYPE zdsl-uom,
* lgort TYPE zdsl-lgort,
* lot TYPE zdsl-lot,
* prod_date TYPE zdsl-prod_date,
* ebeln TYPE zdsl-ebeln,
* erdat TYPE zdsl-erdat,
* erzet TYPE zdsl-erdat,
* ernam TYPE zdsl-ernam,
* aedat TYPE zdsl-aedat,
* username TYPE zdsl-username,
* floc TYPE zdsl-floc,
* END OF ty_zdsl.
* declare the one more internal table with reference of your Z table
TYPES: BEGIN OF ty_zdsl_update,
* mandt TYPE zdsl-mandt,
* werks TYPE zdsl-werks,
* pallet_id TYPE zdsl-pallet_id,
* matnr TYPE zdsl-matnr,
* erfmg type ztable-erfmg,
* uom TYPE zdsl-uom,
* lgort TYPE zdsl-lgort,
* lot TYPE zdsl-lot,
* prod_date TYPE zdsl-prod_date,
* ebeln TYPE zdsl-ebeln,
* erdat TYPE zdsl-erdat,
* erzet TYPE zdsl-erdat,
* ernam TYPE zdsl-ernam,
* aedat TYPE zdsl-aedat,
* username TYPE zdsl-username,
* floc TYPE zdsl-floc,
* END OF ty_zdsl_update.
it_zdsl_update[] = it_zdsl[].
modify Ztable from it_zdsl_update