PL/SQL - SPLessons

PL/SQL Comment

Chapter 10

SPLessons 5 Steps, 3 Clicks
5 Steps - 3 Clicks

PL/SQL Comment

PL/SQL Comment

shape Description

The PL/SQL compiler ignores the PLSQL Comment. The comments are nothing but the text in PL/SQL program. Comments are used to record the code. PLSQL Comment can be composed into two types

Single line comments

shape Description

Single line comments starts with two dashes - -. It can start anywhere on the line and ends anywhere on the line.

shape Syntax

SQL> – – Single Line comment;

shape Examples

The following example describes the single line comment in PL/SQL program.

 sql>DECLARE
  2  how many NUMBER;
  3  num_tables NUMBER;
  4  BEGIN
  5   --Begin processing
  6  SELECT COUNT(*) INTO how many
  7  FROM USER_OBJECTS
  8  WHERE OBJECT_TYPE='TABLE'; --Check number of tables
  9  num_tables :=how many; --Compute some other values
 10  END;
 11  /
PL/SQL program is successfully executed.

The above example describes the PL/SQL standard program for composing single line comments.

Multiple line comments

shape Description

The multiple line comments starts with /* and ends with */ a symbol and can be applied to multiple lines. One can utilize multiple comments to comment-out different blocks of code.

shape Syntax

SQL> /* Multiple Comment line1
Multiple Comment line2 */

shape Examples

The below example describes multiple line comments in PL/SQL  program.

SQL> DECLARE
  2  some_condition BOOLEAN;
  3  pi     NUMBER:=3.1415936;
  4  radius NUMBER:=15;
  5  area   NUMBER;
  6  BEGIN
  7  /*Perform some simple tests and assignments*/
  8  IF 2+2=4 THEN
  9  some_condition:=TRUE;
 10  /* We expect this THEN to always be performed*/
 11  END IF;
 12  /* The following line computes the area of a circle using pi,
 13  which is the ratio between the circumstance and diameter.
 14  After the area is computed,the result is displayed.*/
 15  area:=pi*radius**2;
 16  DBMS_OUTPUT.PUT_LINE('The area is:'||TO_CHAR(area));
 17  END;
 18  /

The area is: 706.858335
PL/SQL procedure is successfully completed.

The above example describes the PL/SQL standard program for composing multiple line comments.

Summary

shape Key Points

  • PLSQL Comment – A remark is a content that the PL/SQL compiler overlooks.
  • Single line comments – It begins with delimiter in PL/SQL.
  • Multiple line comments – It begins with slash-asterisk and ends with asterisk-slash.