how to update a specific line for a single record

hi All,

can anyone help me with the procedure of… how to update a single line or multiple line for a sing record in PurchTable.

in form , I have a table in which i created a record1. when i create a line for the corresponding record1 it gets updated. similarly when i create a new record2 in table and create a corresponding line for the record2. it gets updated but in the same lines …

i mean all the lines in the same place… its not updating for a specific record → specific line

the output should be like this.

Record 1 ------> line 1

Record 2 ------> line 2

But what i am getting is

Record 1 ------> Line 1

Record 2 --------> Line1, Line 2

.Record 3 ------> Line1, line 2,line3…

Can anyone solve this issue for me…