TurboIMAGE/XL Database Management System Reference Manual (30391-90012)

Chapter 5 211
TurboIMAGE/XL Library Procedures
DBLOCK
If you specify a data item of type P, U, or Z in a lock descriptor, TurboIMAGE/XL checks
that the value is valid for that data item type. The following checks are made:
• If the data item is type P, the right half of the right most byte must contain a sign and
all preceding nibbles must contain decimal digits represented in Binary Coded Decimal
(BCD) format. For example, if a data item is defined as type P with a length of 20, the
format must be as shown here:
Figure 5-4. Lock Descriptor Format
This would be declared in COBOL II as 19 digits plus a sign or 20 nibbles (P20 in the
schema):
S9(19) COMP-3
Type P data item used in a lock descriptor cannot exceed 28 nibbles (7 halfwords) in
length. The locking system treats all sign digits other than 1101
2
as identical. 1101
2
is
assumed to be a negative sign.
• If the data item is type U, the value cannot contain any lowercase alphabetic characters
in the range of a through z (for non-native language use only).
• If the data item is type U or X, and a lock specifies an inequality, the language of the
database is used.
• If the data item is type Z, each byte preceding the last one must contain an 8-bit digit
represented in ASCII format and the last byte must contain a value representing a digit
and a sign.
• If the data item is type R, it is sorted based on the HP 3000 floating point number
format.