Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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.
Naming Conventions The similar naming conventions apply to all PL/SQL program items and units including the variables, cursors, constants, cursor variables, procedures, exception
Cursor Attributes The Cursors and cursor variables have 4 attributes which give you helpful information about the execution of a data manipulation statement. Syntax:
Avoid the NOT NULL Constraint In the PL/SQL, using the NOT NULL constraint incur a performance cost. Consider the illustration as shown below: PROCEDURE calc_m IS m NUMB
How Exceptions Propagate ? Whenever an exception is raised, and if the PL/SQL cannot find a handler for it in the present subprogram or block, the exception propagates. That is
Multiple Assignment- SQL SQL supports multiple assignment to local variables and also applies multiple assignment semantics in SET clauses of UPDATE statements, but does not
COMMIT Statement The COMMIT statement explicitly makes everlasting changes to the database during the present transaction. The Changes made to the database are not considered e
%TYPE: This attribute gives the datatype of a formerly declared collection, cursor variable, object, field, record, database column, or variable. Datatype: This is simply
LIKE Operator You use the LIKE operator to compare the character value to a pattern. The Case is significant. LIKE returns the Boolean value TRUE when the character patterns mat
Operator Precedence The operations within an expression are completed in a particular order depending on their precedence (priority). The table shows the default order of the op
Special cases of projection This section describes the identity projection, r {ALL BUT}, and the projection on no attributes, r { }, which yields TABLE_DUM when r is empty, ot
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd