Data Definition Language (DDL) Reference Manual

Definition Attributes
Data Definition Language (DDL) Reference Manual—529431-004
6-42
SQLNULLABLE
Because of this restriction, the maximum size that can be specified on an SQL-nullable
line item is two bytes less than the numbers shown above. These two bytes are the
indicator that shows whether the line item is null.
SQLNULLABLE cannot be specified for FILLER or BIT line items; these types of items
can never be SQL-nullable. SQLNULLABLE cannot be specified on a group that
contains a FILLER or BIT line item unless that line item is explicitly declared to be NOT
SQLNULLABLE.
Neither SQLNULLABLE nor NOT SQLNULLABLE can be specified on an 88 condition-
name line item or an 89 enumeration line item.
The dictionary fields that support SQL-nullable items are described in Appendix D,
Dictionary Database Structure.
In Example 6-32 on page 6-42:
•
Because DEF A has no specification regarding SQL-nullability, line items within the
group are not SQL-nullable unless individually declared to be SQL-nullable.
•
Because DEF B is specified as SQLNULLABLE, line items within that group are
SQL-nullable unless individually not to be SQL-nullable.
•
Semantically, A and B are equivalent.
Example 6-32. SQLNULLABLE Clause
DEF A.
02 name PIC X(25). ! Not nullable
02 nickname PIC X(10) VALUE SQLNULL SQLNULLABLE.
02 salary TYPE BINARY. ! Not nullable
02 hire-date TYPE DATE. ! Not nullable
END.
DEF B SQLNULLABLE.
02 name PIC X(25).
02 nickname PIC X(10) VALUE SQLNULL SQLNULLABLE.
02 salary TYPE BINARY.
02 hire-date TYPE DATE.
END.