19.7. Dependency graphs for transactions
In this section we develop a graphical representation for schedules of operations of transactions. Any necessary ordering of the operations within a transaction is indicated in its graph. Figure 19.5 shows the transactions Sum and Transfer where Transfer is as used in the previous sections, and Sum is defined as follows:
read-balance(account-A); read-balance(account-B); print(account-A + account-B).
Figure 19.5. Graphical representation of the Sum and Transfer transactions.
Note that the print(account-A + account B) statement is shorthand for 'add the balances of the two accounts, found as the result of ...
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