Simple Variables
A
simple variable is a single data item
. It contains only one value
. A simple variable can be any of the basic data types, such as integer or varchar, with the exception of table_key and object_key as described in
Data Types.
How You Can Declare Simple Variables
The syntax for declaring a simple variable is:
name = datatype [with null|not null] [not default|with default|[with] default defaultvalue]
The following example shows a local variable declaration for an integer variable:
i = integer;
By default, all simple variables are nullable. If you do not want the variable to be nullable, you must include the not null clause in the declaration, for example:
i = integer not null;
By default, all numeric simple variables are assigned a default value of zero, and all character simple variables are assigned a default value of the empty string (''). If you want to specify a different default value, you must include the default clause. The default value must be null, a literal, or one of the system constants defined in the Language Reference Guide online help, for example:
i = integer not null default false;
The with null, not default, and with default (without a value) clauses are provided for syntactic compatibility with SQL, but they have no effect in OpenROAD.
How You Can Use Simple Variables
To make use of a simple variable, use the variable name. For example, to assign the value of Smith to the person variable, use the following statement:
person = 'Smith';
Individual elements in a reference variable or an array can be simple variables, as shown in the illustration in
Variables.
In this illustration, Film is a reference variable with three attributes
. Each of these attributes is a simple variable
. Similarly, Movies is an array and each individual element in the array is a simple variable.
In a 4GL script, you can use simple variables as reference or array variable elements in any context that you can use other simple variables, for example:
film.Director = 'Hitchcock';
if movies[].Title = 'ANNIE HALL' then ...
In the first example, film.Director is a simple variable that is an element of a reference variable. In the second, movies[].Title is a simple variable that is an element of an array.
For information about referencing the individual elements in a reference or array variable, see
Reference Variables and
Dynamic Array Variables.