SQL/MX 3.x Query Guide (H06.22+, J06.11+)

SQL/MX Operators
HP NonStop SQL/MX Query Guide—640323-001
7-79
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 constrains 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)