Hi Jürgen , thanks for your reply.
1- I have used batch input
2-the customer has to be created with the first line and extended with the other lines.
3- The structure of my file is :
1st line : company codedata 1 , Sales area data 1 , customerA 's old number , general dataA,
2nd line : company codedata2, Sales orga 2, customerA 's old number , general dataA
3rd line : company codedata3, Sales orga 3, customerA 's old number , general dataA
4th line : company codedata 1 , Sales area data 1 , customerB 's old number , general dataB,
5th line : company codedata2, Sales orga 2, customerB 's old number , general dataB
....
The customer old number can help for the extension ?