Concurrent updation of z table

Dear Experts,

If a z-transparent table is being updated by a batch program , and sometime during this process, another batch job calling the same program but with different selections needs to update the same table, what happens?

Will there be some data not updated by either programs if the keys are different?

How does SAP handle this?

Also, what then if there is overlapping selections?

Both jobs ran and completed successfully but I am not sure the data if properly updated as there are too many entries.

regards

Bass