Literals in pl/sql, PL-SQL Programming

Assignment Help:

Literals

A literal is an explicit numeric, string, character, or Boolean value not represented by an identifier. Numeric literal 147 and the Boolean literal FALSE are some of the examples.

Numeric Literals

The 2 kinds of numeric literals can be used in an arithmetic expression: integers & reals. The  integer literal is an optionally signed whole number without a decimal point. Some of the examples are shown below:

030, 6, -14, 0, +32767

A real literal is an optionally signed whole or fractional number with a decimal point. Some of the examples are shown below:

6.6667, 0.0, -12.0, 3.14,159, +8300.0, 0 .5 25

The PL/SQL considers numbers like 12.0 and 25. to be real even if they have integral values.

The Numeric literals cannot contain dollar signs or commas, however can be written using the scientific notation. Just suffix the number with an E (or e) followed by an optionally signed integer. A few examples are shown below:

2E5 1.0E-7 3.14159e0 -1E38 -9.5e-3

The E stands for "times ten to the power of." As the next illustration represents, the number after E is the power of ten by which the number before E must be multiplied (the double asterisk (**) is the exponentiation operator):

5E3 = 5 10**3 = 5 1000 = 5000

The number after E also correspond to the number of places the decimal point shift. In the last illustration, the implicit decimal point shifted three places to the right. In this illustration, it shifts three places to the left:

5E-3 = 5 10**-3 = 5 0.001 = 0.005

As the example below shows, if the value of a numeric literal falls outside the range 1E-130... 10E125, you obtain a compilation error:

DECLARE

n NUMBER;

BEGIN

n := 10E127; -- causes a 'numeric overflow or underflow' error

Character Literals

A character literal is an individual character enclosed by single quotes (apostrophes). The Character literals include all the printable characters in the PL/SQL character set: numerals, letters, spaces, and special symbols. Some examples are as shown:

'Z' '%' '7' ' ' 'z' '('

The PL/SQL is case sensitive within the character literals. For example, PL/SQL considers

the literals 'Z' and 'z' to be different. Also the character literals '0'..'9' are not equivalent to the integer literals but can be used in the arithmetic expressions as they are implicitly convertible to integers.

String Literals

A character value can be represented by an identifier or explicitly written as a string literal that is a sequence of zero or more characters enclosed by single quotes. Several examples are shown below:

'Hello, world!'

'XYZ Corporation'

'10-NOV-91'

'He said "Life is like licking honey from a thorn."'

'$1,000,000'

All the string literals except the null string ('') have datatype CHAR. Given that the apostrophes (single quotes) delimit string literals, how do you show an apostrophe within a string? As the next illustration shows, you write two single quotes that are not similar as writing a double quote:

"'Don't leave without saving the work."

The PL/SQL is case sensitive within string literals. For illustration, PL/SQL considers the following literals to be different:

'baker'

'Baker'

Boolean Literals

The Boolean literals are the predefined values TRUE, FALSE, & NULL (which stand for an unknown, missing, or inapplicable value). Keep in mind; the Boolean literals are values, and not the strings. For illustration, TRUE is no less a value than the number 25.


Related Discussions:- Literals in pl/sql

Sql script to create and populate the tables, Create the four tables and po...

Create the four tables and populate them with the given data. Answer the following queries in SQL. 1. Get all part-color/part-city combinations. Note: Here and subsequently, the

Using aliases-declarations in sql, Using Aliases The Select-list items f...

Using Aliases The Select-list items fetched from a cursor related with the %ROWTYPE should have simple names or, if they are expressions, should have aliases. In the example bel

Union all - sql, UNION ALL - SQL Further varieties of UNION arise when...

UNION ALL - SQL Further varieties of UNION arise when we replace the key word DISTINCT by ALL in any of the foregoing examples, as in Example. ALL specifies that if row r appe

Parameter and keyword description - loop statements, Parameter and Keyword ...

Parameter and Keyword Description: label_name: This is an undeclared identifier which optionally labels a loop. When used, the label_name should be enclosed by double ang

Effects of null for union - sql, Effects of NULL for union - SQL The ...

Effects of NULL for union - SQL The treatment of NULL in invocations of EXCEPT is as for UNION. This is different from its treatment in those of NOT IN and quantified compari

Using delete - collection method, Using DELETE This process has three ...

Using DELETE This process has three forms. The DELETE removes all elements from the collection. DELETE(n) removes the nth element from the nested table. When n is null, then D

Example of table literal - sql, Example of Table Literal - SQL Exampl...

Example of Table Literal - SQL Example: A Table Literal (correct version) VALUES ('S1', 'C1', 'Anne'), ('S1', 'C2', 'Anne'), ('S2', 'C1', 'Boris'), ('S3', 'C3'

Compare sql and pl/sql, Question 1 . Compare SQL and PL/SQL Question 2 ...

Question 1 . Compare SQL and PL/SQL Question 2 . Write a database trigger to implement the following check condition                          Given the following table

Using cursor attributes - bulk bind performance improvement, Using Cursor A...

Using Cursor Attributes To process the SQL data manipulation statements, the SQL engine must opens an implicit cursor named SQL. This cursor's attributes (%FOUND, %NOTFOUND, %

Unnest operator in sql, UNNEST operator in SQL The inverse operator of...

UNNEST operator in SQL The inverse operator of GROUP is UNGROUP. SQL has an operator, UNNEST, that can be used for similar purposes, but its method of invocation is somewhat p

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