Declarations in sql-pl/sql, PL-SQL Programming

Assignment Help:

Declarations in SQL

Your program stores values in the variables and constants. As the program executes, the value of the variables can change, but the values constants cannot.

 

You can declare the variables and constants in the declarative part of any PL/SQL block, package, or subprogram. The Declarations allocate the storage space for a value, state its datatype, and name the storage location and hence, you can reference it.

 

A couple of examples are shown below:

 

birthday DATE;

emp_count SMALLINT := 0;

The first declaration names a variable of the type DATE. The second declaration names a variable of the type SMALLINT and uses the assignment operator to assign an initial value of zero to the variable.

 

The example next show that the expression following the assignment operator can be arbitrarily complex and can refer to the earlier initialized variables:

 

pi REAL := 3.14159;

radius REAL := 1;

area REAL := pi * radius**2;

 

By default, the variables are initialized to NULL. So, these declarations are equal:

 

birthday DATE;

birthday DATE := NULL;

 

In the declaration of a constant, the keyword CONSTANT should precede the type of the specifier, as the example below shows:

 

credit_limit CONSTANT REAL := 5000.00;

 

This declaration names a constant of the type REAL and assigns an initial value of 5000 to the constant. The constant must be initialized in its declaration. Or else, you get a compilation error whenever the declaration is elaborated. (The procedure of a declaration by the PL/SQL compiler is known as the elaboration.)


Related Discussions:- Declarations in sql-pl/sql

Aggregate assignment-declarations in sql, Aggregate Assignment The %ROWT...

Aggregate Assignment The %ROWTYPE declaration cannot include an initialization clause. Though, there are two ways to assign values to all fields in a record at once. At First, t

Sql cursor - syntax, SQL Cursor   The Oracle implicitly opens a cursor...

SQL Cursor   The Oracle implicitly opens a cursor to process each SQL statement not related with an explicit cursor. The PL/SQL refers to the most current implicit cursor as t

Create a procedure that update the status, Create a procedure named STATUS_...

Create a procedure named STATUS_SHIP_SP that allows a company to employee in the Shipping Department to update the status of an order to add shipping information. The BB_BASKETSTAT

Object types and collections - performance of application, Use Object Types...

Use Object Types and Collections The Collection types and object types increase your efficiency by allowing for the realistic data modeling. The Complex real-world entities an

Implicit cursors, Implicit Cursors The Oracle implicitly opens a curso...

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

What are decision support systems, (a) What are decision support systems, a...

(a) What are decision support systems, and what role do they play in the business environment? (b) Data warehousing is defined as "a subject-oriented, integrated, non-volatile c

EXCEPTION handling, set serveroutput on declare a number(5); b numb...

set serveroutput on declare a number(5); b number(5); c number(5); begin a:=&a; b:=&b; c:=a/b; dbms_output.put_line(c); exception when zero_divide then d

Use bulk binds - improve performance of application, Use Bulk Binds If...

Use Bulk Binds If SQL statements execute inside a loop using the collection elements as bind variables, context switching between the PL/SQL & SQL engines can slow down the ex

%notfound - explicit cursor attributes, %NOTFOUND The %NOTFOUND is log...

%NOTFOUND The %NOTFOUND is logical, opposite of the %FOUND. The %NOTFOUND yields FALSE if the last fetch returned a row, or TRUE when the final fetch failed to return a row. I

Package dbms output in pl/sql, DBMS_OUTPUT: The Package DBMS_OUTPUT en...

DBMS_OUTPUT: The Package DBMS_OUTPUT enables you to display output from the PL/SQL subprograms and blocks, that makes it easier to test and debug them. The procedure put_ line

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd