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!
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 NUMBER NOT NULL;
a NUMBER;
b NUMBER;
BEGIN
...
m := a + b;
As m is constrained by the NOT NULL, the value of the expression a + b is assigned to a temporary variable, that is then tested for the nullity. If the variable is not null, its value is assigned to m. Or else, an exception is raised. Though, if m were not constrained, then the value would be assigned to m directly. A more accurate way to write the last illustration shown below:
m NUMBER; -- no constraint
IF m IS NULL THEN ... -- enforce constraint programmatically
END;
Parameter and Keyword Description: table_reference: This keyword identifies the table or view that should be accessible when you execute the UPDATE statement, and for wh
Other monadic - SQL In 2VL there are just 4 (2 2 ) monadic operators, of which negation is really the only "useful" one. When a third truth value is introduced we have 27 (3 3
Varrays versus Nested Tables The Nested tables are differing from varrays in the following ways: 1) Varrays have a maximum size, while nested tables do not. 2) Varrays are
Implicit Cursors The Oracle implicitly opens a cursor to process each SQL statement not related with an explicitly declared cursor. The PL/SQL lets you refer to the most recen
Complete the following steps to create a procedure to calculate the tax on an order. The BB_TAX table contains the states that require taxes to be submitted for Internet sales. If
Cursor Variables: To execute the multi-row query, the Oracle opens an unnamed work region that stores the processing information. You can use an explicit cursor that names
Overriding Default Locking By default, the Oracle locks the data structures for you automatically. Though, you can request exact data locks on rows or tables when it is to you
Fetching from a Cursor Variable The FETCH statement retrieve rows one at a time from the product set of a multi-row query. The syntax for the same is as shown: FETCH {curso
Defining and Declaring Collections To create the collections, you must define a collection type, and then declare the collections of that type. You can define the VARRAY types a
Datatypes Every constant and variable has a datatype that specifies the storage format, constraints, and the valid range of values. The PL/SQL gives a variety of predefined dat
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