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

What is a record, What Is a Record  ? A record is a group of related...

What Is a Record  ? A record is a group of related data items that stored in the fields, each with its own name and datatype. Assume that you have different data about an em

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

Execute your documentation in oracle, Using research notes and Oracle docum...

Using research notes and Oracle documentation plan and execute an upgrade of an installation of Oracle 10g to Oracle 11g release 1. To do this you must show in screen shots and wri

Relational shema.., Find the account numbers of all customers whose balance...

Find the account numbers of all customers whose balance is more than 10,000 $

Overloading, Overloading The PL/SQL overloads the subprogram names. T...

Overloading The PL/SQL overloads the subprogram names. That is, you can use similar name for few different subprograms as long as their formal parameters differ in the number

Using raise_application_error - user-defined exceptions, Using raise_applic...

Using raise_application_error The Package DBMS_STANDARD that is supplied with Oracle gives language facilities that help your application to interact with Oracle. For illustra

Providing results of queries, Providing Results of Queries Expressing ...

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.

Use native dynamic sql - improve performance of application, Use Native Dyn...

Use Native Dynamic SQL A few programs (a normal-purpose report writer for illustration) should build and process a variety of SQL statements at run time. Therefore, their full

Need to change mysql query to pdo, Need to change mysql query to PDO Pro...

Need to change mysql query to PDO Project Description: I want someone to convert me 1 .php file that includes some sql/mysql stuff to PDO is a very small file. Skills requ

Parameter and keyword description - procedures, Parameter and Keyword Descr...

Parameter and Keyword Description: procedure_name The user-defined procedure is declared by this construct. parameter_name: This identifies the formal parameter t

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