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!
Object Types
An object type is a user-defined complex datatype which encapsulates the data structure along with the functions and procedures required to manipulate the data. The variables which form the data structure are known as the attributes. The procedures and functions which characterize the behavior of the object type are known as the methods.
Presently, you cannot define object types within the PL/SQL. They should be CREATED and stored in an Oracle database, where they can be shared by various programs.
When you define an object type (in the SQL*Plus for illustration) using the CREATE TYPE statement, you can create an abstract template for various real-world object. The templates specify only those attributes and behaviors the object will require in the application atmosphere.
The data structure formed by the set of attributes is public. Though, well-behaved programs do not manipulate it directly. Rather than, they use the set of methods provided. In that way, the data is kept in an appropriate state. At the run time, when the data structure is filled with values, you have formed an instance of an object type. You can create as numerous instances (typically known as objects) as you require.
Syntax:
SELECT INTO Statement The SELECT INTO statement retrieve data from one or more database tables, and then assigns the selected values to the variables or fields. Syntax:
CHECK Constraints in SQL A CHECK constraint is a table constraint defined using the key word CHECK, as already illustrated in several examples in this chapter. In particular,
Example of Alternative formulation as a table constraint Example: Alternative formulation as a table constraint ALTER TABLE EXAM_MARK ADD CONSTRAINT Must_be_enrolled_to_
DELETE Statement The DELETE statement eliminates whole rows of data from the specified table or view. Syntax:
Main features of PL/SQL A good way to get familiar with PL/SQL is to look at a sample program. The below program processes an order for tennis rackets. At first, it declares a
Dynamic Ranges The PL/SQL lets you determine the loop range dynamically at run time, as the example below shows: SELECT COUNT(empno) INTO emp_count FROM emp; FOR i IN 1..emp_cou
EXCEPTION_INIT Pragma The pragma EXCEPTION_INIT relates an exception name with an Oracle error number. Which allow you to refer to any internal exception by the name and to wri
Using Subqueries A subquery is a query (typically enclosed by parentheses) that appears within another SQL data manipulation statement. If evaluated, the subquery gives a va
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
Effect of Anonymous Columns Now, recall that a VALUES expression denotes a table with undefined column names. If an initial value is to be specified when a base table is creat
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