NOT NULL attribute
The NOT NULL
attribute specifies that the field does not accept
NULL
values.
Syntax
NOT NULL
Usage
The NOT NULL
attribute requires that the field contains a non-null value. It
can be specified explicitly in the form field definition, or in the corresponding
column definition in the database schema file. If no column is associated to the
field, the NOT NULL
attribute can also be used in the type
definition of FORMONLY
fields.
The NOT NULL
attribute is effective only when the field name appears in the
list of screen fields of an INPUT
or INPUT ARRAY
statement.
If a DEFAULT
attribute is used for the field and the input dialog does not
use the WITHOUT DEFAULTS
option, the runtime system assumes that
the default value satisfies the NOT NULL
attribute.
Unlike the REQUIRED
attribute which has no effect when the
INPUT
dialog uses the WITHOUT DEFAULTS
option,
the NOT NULL
attribute is always checked when validating a
dialog.
Example
EDIT f001 = customer.city, NOT NULL;