Oracle SQL noun: TRANSACTION

set transaction starts a new transaction and defines some characteristics of this transaction:

• Read-only or writable. (Setting the transaction to read only by user SYS is ignored)
• Isolation level: serializable or read committed. read committed is the default.
• The used rollback segment (ignored if Oracle runs in automatic undo mode)
• The name of the transaction. Naming transactions is especially useful in distributed database environments to resolve in-doubt transactions.

The set transaction statement is optional, however, if it is used, it must be the first statement in a transaction.

Transactions