Inserting data to Store with same ID

Subj.

Grid with data inserted with store.add()

BUT: Inserted data can be:

ID,NAME,FIELD1,FIELD2,COUNT

{1,'test','kaka','12345',8}

{2,'test2....}

...

{1, 'test....,,,14}

So, first record with id=1 inserted;

When I insert second record with id=1, it breaks.

So what? How can I (automatically) update data in Store with same IDs to have in result

{1,'test','kaka','12345',22)

except of

{1.... 8)?

is it able using frontend, with no backend use?

Inserting data to Store with same ID