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Oracle PL/SQL Language Pocket Reference by Chip Dawes, Steven Feuerstein, Bill Pribyl

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Database Interaction and Cursors

PL/SQL is tightly integrated with the underlying SQL layer of the Oracle database. You can execute SQL statements (UPDATE, INSERT, DELETE, and SELECT) directly in PL/SQL programs. You can also execute Data Definition Language (DDL) statements through the use of dynamic SQL (DBMS_SQL in Oracle7 and Oracle8, native dynamic SQL in Oracle8i). In addition, you can manage transactions with COMMIT, ROLLBACK, and other Data Control Language (DCL) statements.

Transaction Management

The Oracle RDBMS provides a transaction model based on a unit of work. The PL/SQL language supports most, but not all, of the database model for transactions (you cannot, for example, ROLLBACK FORCE). Transactions begin with the first change to data and end with either a COMMIT or ROLLBACK. Transactions are independent of PL/SQL blocks. Transactions can span multiple PL/SQL blocks, or there can be multiple transactions in a single PL/SQL block. The PL/SQL supported transaction statements are: COMMIT, ROLLBACK, SAVEPOINT, SET TRANSACTION, and LOCK TABLE. Each is detailed here:

COMMIT

COMMIT [WORK] [COMMENT text];

COMMIT makes the database changes permanent and visible to other database sessions. The WORK keyword is optional and only aids readability—it is rarely used. The COMMENT text is optional and can be up to 50 characters in length. It is only germane to in-doubt distributed (two-phase commit) transactions. The database statement COMMIT FORCE for distributed transactions is not ...

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