1. Explain the following statement:

1. Explain the following statement: a transaction is a logical unit of work.

Acceptance of an incomplete transaction will yield an inconsistent database state. To avoid such a state, the DBMS ensures that all of a transaction's database operations are completed before they are committed to the database. For example, a credit sale requires a minimum of three database operations:

1. An invoice is created for the sold product.
2. The product's inventory quantity on hand is reduced.
3. The customer accounts payable balance is increased by the amount listed on the invoice.

If only parts 1 and 2 are completed, the database will be left in an inconsistent state. Unless all three parts (1, 2, and 3) are completed, the entire sales transaction is canceled.