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

Package dbms pipe in pl/sql, DBMS_PIPE: The Package DBMS_PIPE allows va...

DBMS_PIPE: The Package DBMS_PIPE allows various sessions to communicate over the named pipes. (A pipe is a region of memory used by one of the process to pass information to

Recursion versus iteration, Recursion versus Iteration Dissimilar the i...

Recursion versus Iteration Dissimilar the iteration, recursion is not crucial to PL/SQL programming. Any problem which can be solved using recursion can be solving using the it

Change sql file into csv for product registration, Change Sql file into CSV...

Change Sql file into CSV for product registration on Magento Project Description: I have a set of files that are in Sql format and could like for a developer to help me with

Explicit cursors, Explicit Cursors The set of rows returned by the que...

Explicit Cursors The set of rows returned by the query can include zero, one, or multiple rows, depending on how many rows meet your search criteria. Whenever a query returns

Write a stored procedure, a. Create a table odetails_new. It has all the a...

a. Create a table odetails_new. It has all the attributes of odetails and an additional column called cost, whose values are the product of the quantity and price of the part bein

Magento change address format depending on store, Magento change address fo...

Magento change address format depending on store Project Description: What I need is that depending on the store in which the customer bought the address should change the fo

Updating by replacement, Updating by replacement Syntax: UPDAT...

Updating by replacement Syntax: UPDATE ENROLMENT SET Name = 'Ann' WHERE StudentId = SID ('S1'); Note the use of SET, as already noted in connection with direct a

Tautologies, Tautologies: Above given table allows us to read the trut...

Tautologies: Above given table allows us to read the truth of the connectives in the next manner. Just expect we are looking at row three. It means this says that, if there P

In out mode - parameter modes, IN OUT Mode An IN OUT parameter passes ...

IN OUT Mode An IN OUT parameter passes initial values to the subprogram being called and return efficient values to the caller. Within the subprogram, an IN OUT parameter acts

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

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