Consider a transaction that transfers funds between two bank accounts. It can be structured into two subtransactions: one to debit the first account and the second to credit the second account. Describe howthis can be done in (a) the hierarchical model and (b) the peer model.

What will be an ideal response?

In the hierarchical model the parent initiates a debit subtransaction and if it completes
successfully, initiates a credit subtransaction. When the latter completes the parent
calls commit. In the peer model the two subtransactions can be initiated concurrently.
If they both complete successfully, the parent commits causing the subtransactions to
commit. If not, the parent aborts, causing the subtransactions to abort. Alternatively,
the debit subtransaction could communicate directly to the credit subtransaction,
informing it of whether or not it was successful, and the credit transaction could could
make the deposit appropriately.