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

Procedures - syntax, Procedures The procedure is a subprogram which can...

Procedures The procedure is a subprogram which can take parameters and be invoked. Normally, you can use a procedure to perform an action. The procedure has 2 sections: the spe

Example of group by and collect operator, Example of GROUP BY and COLLECT O...

Example of GROUP BY and COLLECT Operator Example: Using GROUP BY and COLLECT to obtain C_ER2 SELECT CourseId, CAST ( COLLECT (ROW (StudentId, Mark)) AS ROW (Studen

Mysql developer/programmer, Project Description: I want somebody who can...

Project Description: I want somebody who can help me with an idea that I have been working on for a few months now. The person will require extensive knowledge of warcraft 3 PvP

When are constraints checked - sql, When Are Constraints Checked Unde...

When Are Constraints Checked Under the model constraints are conceptually checked at all statement boundaries (and only at statement boundaries). By default the same is true

Pits, PITS Depressions in secondary cell wall is called pit. A pi...

PITS Depressions in secondary cell wall is called pit. A pit present on the free cell wall surface without its partner is called Blind pit. It consists of 2 parts -

Records - syntax, Records Records are the items of the type RECORD. The...

Records Records are the items of the type RECORD. The Records have exclusively named fields that can store the data values of various types. And hence, a record treat associate

Mutual recursion, Mutual Recursion The Subprograms are mutually recursi...

Mutual Recursion The Subprograms are mutually recursive if they directly or indirectly call each other. In the illustration below, the Boolean functions odd & even, that dete

Use external routines - improve performance of application, Use External Ro...

Use External Routines The PL/SQL is particular for the SQL transaction processing. Therefore, several tasks are more quickly completed in a lower-level language like C that is

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

Interesting properties of cross join - sql, Interesting properties of CROSS...

Interesting properties of CROSS JOIN - SQL Compare these with the "interesting properties of JOIN", CROSS JOIN is associative but not commutative. Unlike JOIN and NATURAL JOI

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