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

Chapter 11 501
B-Tree Indices
External Commands and Utilities Affected
Supported Modes of DBFIND
These are modes of DBFIND supported by the B-Tree index feature:
1 do a B-Tree DBFIND if all of the following are true:
• BTREEMODE1 is on.
• The item type is X or U.
• The item has a B-Tree index (explicit or implicit).
• The argument contains wildcard character.
Otherwise execute DBFIND as done without this feature.
For B-Tree DBFINDs, the argument is scanned for the first occurrence of the
wildcard character, and a trailing-@ search is done. Subsequent text in the
key value is ignored.
For B-Tree DBFINDs pertaining to detail data sets, the chain-count is
accurate, and status halfwords 7-8 and 9-10 give the record numbers of the
last entry in the last chain, and the first entry in the first chain of the
super-chain.
For B-Tree DBFINDs pertaining to master data sets, the status halfwords
5-6 (chain-count for detail) reflect the total number of entries qualified in
the master data set. All other fields of the status array return zeroes.
4 do a B-Tree index search, and give accurate chain counts and record
numbers in the status array. For masters, the status array returns the
same information as in B-Tree DBFIND mode 1. The argument is in
structured format described later.
10 do a non-B-Tree DBFIND mode 1 equivalent. This gives the same result as
if there were no B-Tree index.
21 is the same as mode 1, above, but the chain count and record numbers for
last entry and first entry are not accurate. (This is a high-speed version of
mode 1.) For detail data set, the halfwords 5-6, 7-8, and 9-10 have 2
31
−1.
For master data set, the halfword 5-6 has 2
31
−1 and 7-8 and 9-10 have
zeroes. Following this DBFIND, you may do DBGET mode 5 or 6.
24 is the same as mode 4, above, but the chain count and record numbers for
last entry and first entry are not accurate. (This is a high-speed version of
mode 4.) For detail data set, the halfwords 5-6, 7-8, and 9-10 will have
2
31
−1. For master data set, the halfword 5-6 has 2
31
−1 and 7-8 and 9-10
have zeroes. The argument is in structured format described later.