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

Exception handling, Exception handling In the PL/SQL, a warning or erro...

Exception handling In the PL/SQL, a warning or error condition is known as an exception. The Exceptions can be internally defined (by the run-time system) or user defined. The

How exceptions propagate in pl/sql programming?, How Exceptions Propagate ?...

How Exceptions Propagate ? Whenever an exception is raised, and if the PL/SQL cannot find a handler for it in the present subprogram or block, the exception propagates. That is

Delimiters, Delimiters A delimiter is a simple or compound symbol whi...

Delimiters A delimiter is a simple or compound symbol which has a special meaning to PL/SQL. For example, you use delimiters to symbolize an arithmetic operation like additio

Using first and last - collection method, Using FIRST and LAST FIRST a...

Using FIRST and LAST FIRST and LAST return the first and last (minimum and maximum) index numbers in a collection. When the collection is empty, the FIRST and LAST return NULL

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

Assignment of variable - updating a variable, Assignment of Variable - Upda...

Assignment of Variable - Updating a Variable Syntax: SET SN = SID ('S2'); This can obviously be read as "set the variable SN to be equal in value to SID ( 'S2' )".

Updating objects in pl sql, Updating Objects: To change the attributes...

Updating Objects: To change the attributes of objects in an object table, you can use the UPDATE statement, as the illustration below shows: BEGIN UPDATE persons p SET p

Restriction and and - sql, Restriction and AND - SQL Restriction is av...

Restriction and AND - SQL Restriction is available via the WHERE operator, and so it is in SQL. However, by Example showing how a certain simple restriction can be expressed u

Cursor variables as parameters, Cursor Variables As Parameters You can...

Cursor Variables As Parameters You can declare the cursor variables as the formal parameters of the functions and procedures. In the illustration below, you define the REF CUR

Sql queries-oracle , 1- You can check attribute names from each table in D...

1- You can check attribute names from each table in DBF11 by running for example:  desc dbf11.Member;  desc dbf11.Agent;  desc dbf11.Producer; Because some attribute names in

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