TurboIMAGE/XL Database Management System Reference Manual MPE/iX V6.5 (30391-90011)

Chapter 5 185
TurboIMAGE/XL Library Procedures
DBGET
6 Backward Chained Read.
Read the previous entry in the current chain, or the
previous qualified entry for a B-Tree DBFIND. This is the
entry referenced by the internally maintained backward
pointer (argument parameter is ignored). Super-chains are
traversed for detail data sets.
If your database is enabled for third-party indexing (TPI),
refer to your vendor documentation for additional
information.
7 Calculated Read. (Master data sets only.) Read the entry
with a key item value that matches the value specified in
argument. The entry is in the master data set specified by
dset.
8 Primary Calculated Read. (Master data sets only.) Read
the entry occupying the primary address of a synonym
chain using the key item value specified in argument to
locate the entry. The key item value returned is always
that of the primary entry and might not match the value
specified in argument. (Refer to chapter 10 for synonym
chain description.)
If your database is enabled for third-party indexing (TPI), refer to your
vendor documentation for additional DBGET modes. The section on DBUTIL
in chapter 8 of this book has a brief description of the TPI option.
status is the name of a 10-halfword array in which TurboIMAGE/XL returns
status information about the procedure. If the procedure executes
successfully, the status array contents are:
Element Contents
1 If the procedure succeeds, the return status is 0. Table
5-12. describes the contents of element 1 when the
procedure does not succeed.
2 Length of the logical entry read into the buffer array in
halfwords.
3-4 Word record number of the data entry read.
5-6 Word zero, unless the entry read is a primary entry in
which case it is the number of entries in the synonym
chain.
7-8 Word record number of the preceding entry in the chain of
the current path for the detail data sets. Zeroes for master
data sets.
9-10 Word record number of the next entry in the chain of the
current path for the detail data sets. Zeroes for master
data sets.