Object Type:

The object type is a user-defined composite datatype which encapsulates a 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 functions and procedures which characterize the behavior of the object type are known as methods.

We typically think of an object (like a car, person, or bank account) as having behaviors and attributes. For illustration, a baby has the attributes age, gender, and weight, and the behaviors drink, eat, and sleep. The Object types maintain this perspective when you sit down to write an application.

Whenever you define an object type using the CREATE TYPE statement, you create an abstract template for several real-world objects. The template specifies only those behaviors & attributes that the object which will require in the application atmosphere. For illustration, an employee has numerous attributes, but usually only a few are required to fill the requirements of an application.

Figure: Form Follows Function

 

Assume that you should write a program to allocate the employee bonuses. Not all the employee attributes are required to solve this problem.Therefore, you design an abstract employee who has the problem-specific attributes as: name, job title, id_number, department, salary, and rank. Then, you can identify the operations required to handle an abstract employee. For illustration, you require an operation which lets Management change the rank of an employee.

Later, you define a set of variables to present the data, and a set of subprograms to perform the operations. Lastly, you encapsulate the methods and attributes in an object type. The data structure created by the set of attributes is public. Though, well-behaved programs do not influence it directly. Rather, they use the set of methods provided. In that way, the employee data is kept in an appropriate state.

At run time, if the data structure is filled with values, you have created an illustration of an abstract employee. You can create as numerous instances (usually known as objects) as you require. Each object has the name, job title, and number, and so on of an actual employee. This data is accessed or changed only by the methods related with it. Therefore, the object types let you create objects with the well-defined behavior and attributes.

Figure: Object Type and Objects (Instances) of That Type

Posted Date: 10/6/2012 7:56:13 AM | Location : United States

Ask an Expert

Related Discussions:- Object type in pl/sql, Assignment Help, Ask Question on Object type in pl/sql, Get Answer, Expert's Help, Object type in pl/sql Discussions

Write discussion on Object type in pl/sql
Your posts are moderated

Write your message here..

Related Questions

Write a pl/sql anonymous block that accepts an employee id, Based on the EM... Based on the EMPLOYEE table created in Assignment #1, write a PL/SQL anonymous block that accepts an employee ID from the user input and finds whether the employee ID is in the EMP

Assignment source not a literal - variable, Assignment Source Not a Literal... Assignment Source Not a Literal - Variable Syntax: SET SN = SID (SUBSTRING (SN.C FROM 1 FOR 1)||'5');

Avoid the not null constraint - performance of application, Avoid the NOT N... 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

Procedures in pl/sql, Procedures   The procedure is a subprogram which... Procedures   The procedure is a subprogram which performs a specific action. You write procedures using the syntax as shown below: PROCEDURE name [(parameter[, parameter, .

Data types in sql - decimal, Data Types in SQL - Decimal DECIMAL, NUME... Data Types in SQL - Decimal DECIMAL, NUMERIC, REAL, FLOAT and various other terms for various sets of rational numbers. When these key words are specified for the declared typ

Data types in sql, Data Types in SQL SQL's concept does not differ sig... Data Types in SQL SQL's concept does not differ significantly from that defined in the theory book, apart from that business concerning NULL. However, the theory book equates

Parameter & keyword description - functions, Parameter & Keyword Descriptio... Parameter & Keyword Description: function_name: The user-defined function is identifying by that keyword. parameter_name: This identifies the formal parameter that

Declaring a cursor, Declaring a Cursor The Forward references are not ... 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

For-loop -iterative control, FOR-LOOP While the number of iterations thr... FOR-LOOP While the number of iterations through a WHILE loop is unknown till the loop completes, then the number of iterations through a FOR loop is known before the loop is ent

Advantages of exceptions, Advantages of Exceptions Using the exception... Advantages of Exceptions Using the exceptions for the error handling has many benefits. Without an exception handling, every time you issue a command, you should ensure for th