Lexical unit in PL/SQL
Lexical unit can be classified as
- Delimiters
- Identifiers
- Literals
- Comments
Delimiters in PL/SQL
Symbol | Meaning |
+ | addition operator |
% | attribute indicator |
‘ | character string delimiter |
. | component selector |
/ | division operator |
( | expression or list delimiter |
) | expression or list delimiter |
: | host variable indicator |
, | item separator |
* | multiplication operator |
“ | quoted identifier delimiter |
= | relational operator |
< | relational operator |
> | relational operator |
@ | remote access indicator |
; | statement terminator |
– | subtraction/negation operator |
:= | assignment operator |
=> | association operator |
|| | concatenation operator |
** | exponentiation operator |
<< | label delimiter (begin) |
>> | label delimiter (end) |
/* | multi-line comment delimiter (begin) |
*/ | multi-line comment delimiter (end) |
.. | range operator |
<> | relational operator |
!= | relational operator |
~= | relational operator |
^= | relational operator |
<= | relational operator |
>= | relational operator |
— | single-line comment indicator |
Identifier in PL/SQL
PL/SQL is not case sensitive with respect to identifies
v_first_name
v_perc
V_LAST_NAME
Literal in PL/SQL
Alex, 428, True,
Comments in PL/SQL
Single line comment
Prefix single-line comments with two hyphens (–).
Example:
-- This is Simple Procedure Create or Replace procedure test IS BEGIN dbms_output.put_line('Hi This is Bhavesh Lakhani'); END test;
Multi line comment
Place multiple-line comments between the symbols /* and */
DECLARE v_annual_salary NUMBER (9,2); BEGIN /* Compute the annual salary based on the monthly salary input from the user */ v_annual_salary:= monthly_salary * 12; --The following line displays the annual salary DBMS_OUTPUT.PUT_LINE(v_annual_sal); END;