PL/SQL - Basic Syntax
In this chapter, we will discuss the Basic Syntax of PL/SQL which is a block-
structured language; this means that the PL/SQL programs are divided and written
in logical blocks of code. Each block consists of three sub-parts −
S.No Sections & Description
Declarations
1
This section starts with the keyword DECLARE. It is an optional section and defines all
variables, cursors, subprograms, and other elements to be used in the program.
Executable Commands
2 This section is enclosed between the keywords BEGIN and END and it is a mandatory
section. It consists of the executable PL/SQL statements of the program. It should have
at least one executable line of code, which may be just a NULL command to indicate
that nothing should be executed.
Exception Handling
3
This section starts with the keyword EXCEPTION. This optional section
contains exception(s) that handle errors in the program.
Every PL/SQL statement ends with a semicolon (;). PL/SQL blocks can be nested
within other PL/SQL blocks using BEGIN and END. Following is the basic structure
of a PL/SQL block −
DECLARE
<declarations section>
BEGIN
<executable command(s)>
EXCEPTION
<exception handling>
END;
The 'Hello World' Example
DECLARE
message varchar2(20):= 'Hello, World!';
BEGIN
dbms_output.put_line(message);
END;
/
The end; line signals the end of the PL/SQL block. To run the code from the SQL
command line, you may need to type / at the beginning of the first blank line after
the last line of the code. When the above code is executed at the SQL prompt, it
produces the following result −
In this chapter, we will discuss the Basic Syntax of PL/SQL which is a block-
structured language; this means that the PL/SQL programs are divided and written
in logical blocks of code. Each block consists of three sub-parts −
S.No Sections & Description
Declarations
1
This section starts with the keyword DECLARE. It is an optional section and defines all
variables, cursors, subprograms, and other elements to be used in the program.
Executable Commands
2 This section is enclosed between the keywords BEGIN and END and it is a mandatory
section. It consists of the executable PL/SQL statements of the program. It should have
at least one executable line of code, which may be just a NULL command to indicate
that nothing should be executed.
Exception Handling
3
This section starts with the keyword EXCEPTION. This optional section
contains exception(s) that handle errors in the program.
Every PL/SQL statement ends with a semicolon (;). PL/SQL blocks can be nested
within other PL/SQL blocks using BEGIN and END. Following is the basic structure
of a PL/SQL block −
DECLARE
<declarations section>
BEGIN
<executable command(s)>
EXCEPTION
<exception handling>
END;
The 'Hello World' Example
DECLARE
message varchar2(20):= 'Hello, World!';
BEGIN
dbms_output.put_line(message);
END;
/
The end; line signals the end of the PL/SQL block. To run the code from the SQL
command line, you may need to type / at the beginning of the first blank line after
the last line of the code. When the above code is executed at the SQL prompt, it
produces the following result −
