Block structure
PL/SQL programs are divided up into structures(blocks). Each block contains PL/SQL and SQL statements. A PL/SQL block has the following structure:
[DECLARE
declaration_statements
]
BEGIN
executable_statements
[EXCEPTION
exception_handling_statements
]
END;
/
It says:
| Item | Description |
|---|---|
| declaration_statements | optional, declares the variables used in the rest of the PL/SQL block. |
| executable_statements | the actual executable statements. |
| exception_handling_statements | optional, handle any execution errors. |
Every statement is terminated by a semicolon (;). A PL/SQL block is terminated using the forward slash (/) character.
SQL> SET SERVEROUTPUT ON
SQL>
SQL> DECLARE
2 v_width INTEGER := 3;
3 v_height INTEGER := 2;
4 v_area INTEGER;
5 BEGIN
6 v_area := v_width * v_height;
7 v_width := v_area / v_height;
8 DBMS_OUTPUT.PUT_LINE('area = ' || v_area);
9 DBMS_OUTPUT.PUT_LINE('width = ' || v_width);
10 EXCEPTION
11 WHEN ZERO_DIVIDE THEN
12 DBMS_OUTPUT.PUT_LINE('Division by zero');
13 END;
14 /
area = 6
width = 3
PL/SQL procedure successfully completed.
SQL>
The SET SERVEROUTPUT ON command turns the server output on.