SQL/MX 3.1 Query Guide (H06.23+, J06.12+)

SQL/MX Operators
HP NonStop SQL/MX Release 3.1 Query Guide—663851-001
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UNIQUE_DELETE Operator
UNIQUE_DELETE Operator
DAM Unique Group
The UNIQUE_DELETE operator describes a portion of an execution plan that works on
one row only. It deletes zero or one row.
The UNIQUE_DELETE operator has no child nodes. The description field for this
operator contains:
The following is an example of the UNIQUE_DELETE operator:
prepare TestQuery26 from
delete from tt22 where f1=46;
DESCRIPTION
olt_optimization ....... used
olt_opt_lean ........... used
fragment_id ............ 2
Token Followed by ... Data Type
fragment_id A sequential number assigned to the fragment.
0 is always the master executor and 1 is
reserved for the EXPLAIN plan. Numbers 2 to n
will be ESP or DAM fragments.
integer
parent_frag The fragment_id for the parent of the current
fragment. The value is (none) for the master
executor.
integer
fragment_type Master, ESP, or DP2. text
index_key Expression of the begin key predicates on
index.
expr(text)
key Expression of the key predicate. expr(text)
part_key_predicate Predicate expression specified on partitioning
key. It is displayed only if partitioning key differs
from clustering key.
expr(text)
check_constraint Check constraints in the delete table. expr(text)
olt_optimization Indicates whether an optimization for short,
simple operations is used. Its value is used or
not used.
text
olt_opt_lean Indicates for short, simple operations whether a
further optimization that reduces the physical
size of the plan is used. Its value is used or not
used.
text
iud_type Type of delete followed by table or index name. expr(text)
predicate Expression specified on WHERE clause that is
not reflected in the begin and end predicates.
expr(text)
TP663851.fm Page 83 Monday, October 17, 2011 11:48 AM