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Transaction Control
The Oracle is transaction oriented; that is, Oracle uses the transactions to make sure the data integrity. The transaction is a sequence of SQL data manipulation statements that does a logical unit of work. For illustration, the two UPDATE statements might credit one bank account and debit another.
At the same time, the Oracle makes permanent or undoes all the database changes made by a transaction. If your program fails in the middle of the transaction, the Oracle detects the error and rolls back the transaction. Therefore, the database is restored to its previous state automatically.
You use the ROLLBACK, COMMIT, SAVEPOINT, & SET TRANSACTION commands to control the transactions. The COMMIT makes everlasting and any database changes made during the present transaction. The ROLLBACK ends the present transaction and undoes any changes made as the transaction began. The SAVEPOINT marks the present point in the processing of a transaction. Used with the ROLLBACK, SAVEPOINT undoes part of a transaction. The SET TRANSACTION sets the transaction properties like the read/write access and isolation level.
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Processing Transactions This part describes how to do the transaction processing. You learn the fundamental techniques that safeguard the consistency of your database, involvin
%NOTFOUND The %NOTFOUND is logical, opposite of the %FOUND. The %NOTFOUND yields FALSE if the last fetch returned a row, or TRUE when the final fetch failed to return a row. I
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Selecting Objects: Suppose that you have run the SQL*Plus script below that creates object type Person and object table persons, and that you have settled the table: CREATE
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Declaring a Cursor The Forward references are not allowed in the PL/SQL. Therefore, you must declare a cursor before referencing it in other statements. Whenever you declare a
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