This example examines the work of a user
who is adding new information to the database??”in other words, executing a
transaction.
Oracle and Transactions
A transaction is a work request from a client to insert, update, or delete data. The
statements that change data are a subset of the SQL language called Data Manipulation
Language (DML). Transactions must be handled in a way that guarantees their
integrity. Although Chapter 8 delves into transactions more deeply, we must visit a
few basic concepts relating to transactions now in order to understand the example
in this section:
Transactions are logical and complete
In database terms, a transaction is a logical unit of work composed of one or
more data changes. A transaction may consist of multiple INSERT, UPDATE,
and/or DELETE statements affecting data in multiple tables. The entire set of
changes must succeed or fail as a complete unit of work. A transaction starts
with the first DML statement and ends with either a commit or a rollback.
Oracle also supports autonomous transactions, transactions whose
work is committed or rolled back, but that exist within the context of
a larger transaction.
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