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!
Declaring Objects:
You can use the object types wherever built-in types like CHAR or NUMBER can be used. In the block below, you can declare object r of type Rational. Then, you can call the constructor for the object type Rational to initialize the object. The calls assign the values 6 & 8 to attributes num and den, correspondingly.
DECLARE
r Rational;
BEGIN
r := Rational(6, 8);
DBMS_OUTPUT.PUT_LINE(r.num); -- prints 6
You can declare objects as the formal parameters of the functions and procedures. In that way, you can pass objects to the stored subprograms and from one subprogram to the other. In the later illustration, you use the object type Account to specify the datatype of a formal parameter:
...
PROCEDURE open_acct (new_acct IN OUT Account) IS ...
In the illustration below, you can use object type Account to specify the return type of the function:
FUNCTION get_acct (acct_id IN INTEGER) RETURN Account IS ...
Providing Results of Queries Expressing queries in SQL is the (big) subject. Here I present just a simple example to give you the flavour of things to come in those chapters.
Anatomy of a Command Figure, showing a simple SQL command, is almost identical to its counterpart in the theory book. The only difference arises from the fact that SQL uses a
EXIT-WHEN The EXIT-WHEN statement permits a loop to complete conditionally. Whenever the EXIT statement is encountered, the condition in the WHEN clause is computed. When the co
Components of an Object Type: An object type encapsulates the operations and data. Therefore, you can declare the methods and attributes in an object type specification, but no
Example of COALESCE operator Example: Give the total of marks for each exam (simplified solution) SELECT CourseId, COALESCE ((SELECT SUM (Mark) FROM EXAM_MARK AS EM
How do I display usernames for students from a student table, assigning each student a username initials001 (initials is the actual student initials), and if the students initials
WHEN or THEN Key Constraints Suppose a table has two columns representing a period of time throughout which the information conveyed by the other columns is recorded as having
DELETE Command - SQL Loosely speaking, DELETE removes some existing rows from its target table. Suppose the university decides that course C3 is to be withdrawn. Example shows
Collections: The collection is an ordered group of elements, all of similar type (for illustration, the grades for a class of students). Each element has an exclusive subsc
Ensuring Backward Compatibility The PL/SQL Version 2 permits some abnormal behavior which Version 8 disallows. Particularly, Version 2 permits you to (i) Make the forw
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