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Defining an item Schema DDL
58 U929-J-Z125-9-76
4.2.2 Defining a packed numeric item
[level-number ]item-name TYPE IS FIXED REAL DECIMAL
[ integer-1[,integer-2]].
Packed items can contain numeric values only. They are exclusively used as computational
items by the database programmer and cannot be printed without prior editing by a DML
program. Packed items require less storage space and can be processed faster than
unpacked items.
level-number denotes whether the item is part of a repeating group:
If the item is not to be part of a repeating group, the specified level number should be the
smallest level number in the whole record type.
This is especially important if the item is to be used as a key item.
If the item is to be part of a repeating group, proceed as described on page 66.
item-name specifies the name assigned by the user.
integer-1 and integer-2 are used to describe the value range of an item, where
– integer-1 indicates the number of storage locations the item contains, the maximum
being 18. Each storage location can be filled with a decimal digit.
Default value for integer-1: 18
– integer-2 specifies the position of the decimal point. This has no effect on the number of
storage locations, however. If integer-2 is positive, it denotes the number of digits to the
right of the decimal point; if it is negative, it signals to UDS/SQL how many zeros it is to
append to the item contents when performing calculations.
It follows that if integer-2 is m, specification of integer-2 means a multiplication of the item
contents by 10
-m
.
Default value for integer-2: 0
If at least one of the following assertions applies to an unpacked numeric item, the item
cannot be accessed using SQL, nor can any new records of the record type involved be
inserted:
– number of bytes of storage > 15
– scale factor < 0
– scale factor > number of bytes of storage
A positive scale factor specifies the number of digits to the right of the decimal point, while
a negative scale factor specifies how many zeroes UDS/SQL must append to the item
contents when performing calculations.