Question

See the excerpt below taken from a PL/SQL tutorial. The part I have an issue with is line 3, where it says salary is of length 6. I don’t understand what that means. In the last line of this excerpt, it declares a variable “of length 10” which is then initialized to “HR Dept” which is certainly not 10 characters. What is meant by length?

---

DECLARE

salary  number (6);

* “salary” is a variable of datatype number and of length 6.

When a variable is specified as NOT NULL, you must initialize the variable when it is declared.

For example: The below example declares two variables, one of which is a not null.

DECLARE

salary number(4);

dept varchar2(10) NOT NULL := “HR Dept”;

---

Another example:

DECLARE 



var_salary number(6); 

 var_emp_id number(6) = 1116; 

1116 is not 6 digits. I’m at a loss.

Answer 1

Maximum length. You’d discover this if you tried to store eleven characters into dept or if you started making a cool million each year at whatever your job is.

It’s no different from when you create tables:

create table users (
    id     integer,
    name   varchar(20)
);

In that case, 20 is the maximum length of the name. It doesn’t mean every row has to have a 20-character name.